# Math Is Fun Forum

Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫  π  -¹ ² ³ °

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## #1 2006-02-26 22:51:50

Jai Ganesh
Registered: 2005-06-28
Posts: 47,731

### Algebra

A # 1

If x² + y² + z² = 50, xy + yz + xz = 47 and xyz = 60,
what is the value of
(i) x
(ii) y and
(iii) (x+y+z)³?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #2 2006-02-27 01:03:01

krassi_holmz
Real Member
Registered: 2005-12-02
Posts: 1,905

### Re: Algebra

the numbers are {3,4,5}
12^3=1728

IPBLE:  Increasing Performance By Lowering Expectations.

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## #3 2006-02-27 01:52:40

Jai Ganesh
Registered: 2005-06-28
Posts: 47,731

### Re: Algebra

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #4 2006-02-27 03:11:00

krassi_holmz
Real Member
Registered: 2005-12-02
Posts: 1,905

### Re: Algebra

Thanks.

IPBLE:  Increasing Performance By Lowering Expectations.

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## #5 2006-03-01 04:20:33

Jai Ganesh
Registered: 2005-06-28
Posts: 47,731

### Re: Algebra

A # 2

For waht value of m is 2x³-x²-3mx-24 divisible by x-2?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #6 2006-03-01 04:40:22

krassi_holmz
Real Member
Registered: 2005-12-02
Posts: 1,905

### Re: Algebra

m=2?

IPBLE:  Increasing Performance By Lowering Expectations.

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## #7 2006-03-01 16:09:19

Jai Ganesh
Registered: 2005-06-28
Posts: 47,731

### Re: Algebra

|m|=2 would have been better! The answer is m=-2. Try again, krassi_holmz, probably you made a mistake somewhere.

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #8 2006-03-01 16:11:38

Jai Ganesh
Registered: 2005-06-28
Posts: 47,731

### Re: Algebra

A # 3

If ax³+bx²+x-6 has (x+2) as a factor and leaves a remainder 4 when divided by (x-2), find the values of a and b.

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #9 2006-03-01 20:28:39

Jai Ganesh
Registered: 2005-06-28
Posts: 47,731

### Re: Algebra

A # 4

The sum of two natural numbers is 8. Determine the numbers if the sum of their reciprocals is 8/15.

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #10 2006-03-02 04:52:57

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

### Re: Algebra

A # 3
From the information given, we can deduce that f(-2) = 0 and f(2) = 4.

-8a + 4b -8 = 0
8a + 4b -4 = 4

Subtract the two equations:
16a -4 = -4
16a = 0
a = 0.

Add the two equations: 8b -12 = 4
8b = 16
b = 2.

f(x) = 2x²+x-6

A # 4
Calling the 2 numbers p and q, we know that p+q = 8, and that 1/p+1/q = 8/15.

Cross-multiplying the second equation gives (p+q)/pq = 8/15. We know that (p+q) = 8, so pq must be 15.

The numbers that add to give 8 and multiply to give 15 are 3 and 5.

Why did the vector cross the road?
It wanted to be normal.

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## #11 2006-03-02 16:26:54

Jai Ganesh
Registered: 2005-06-28
Posts: 47,731

### Re: Algebra

Well done, mathsyperson!

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #12 2006-03-02 17:29:28

Jai Ganesh
Registered: 2005-06-28
Posts: 47,731

### Re: Algebra

A # 5

If one of the roots of the equation x²-3x+q=0 is twice the other, find the value of q.

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #13 2006-03-06 20:12:43

Jai Ganesh
Registered: 2005-06-28
Posts: 47,731

### Re: Algebra

A # 6

If the ratio of the roots of the equation ax²-2ax+b=0 is equal to that of ax²-2cx+d=0, then which of the following is true?

(a) a²b=c²d                                      (b) a²c=b²d

(c) a²d=c²b                                      (d) d²b=c²a

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #14 2006-03-08 16:15:28

Jai Ganesh
Registered: 2005-06-28
Posts: 47,731

### Re: Algebra

A # 7

Solve: (x²+1/x²) - 3(x-1/x)-2=0

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #15 2006-03-10 20:09:52

amonjezi
Member
Registered: 2006-03-09
Posts: 9

y=4
and,y=-1

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## #16 2006-03-10 20:15:51

amonjezi
Member
Registered: 2006-03-09
Posts: 9

### Re: Algebra

(x
+1/x^2)-3(x-1/x)-2+2-2=0

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## #17 2006-03-10 20:27:02

amonjezi
Member
Registered: 2006-03-09
Posts: 9

### Re: Algebra

(x^2+1/x^2)-3(x-1/x)-2+2-2=0  then (x+1/x)^2-3(x-1/x)-4=0    if (x+1/x)=y  y=4 and -1  now we solves (x+1/x)=4 and (x+1/x)=-1     these equaition very easy

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## #18 2006-03-11 01:17:49

amonjezi
Member
Registered: 2006-03-09
Posts: 9

### Re: Algebra

hi ganesh
choice (a) or(c) are true

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## #19 2007-04-23 08:20:02

Eeyore
Member
Registered: 2007-04-16
Posts: 8

a7   1 and -1

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## #20 2007-04-23 08:41:04

Eeyore
Member
Registered: 2007-04-16
Posts: 8

A#5   q=2

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## #21 2010-10-22 00:12:45

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: Algebra

Hi ganesh;

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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## #22 2011-02-12 07:37:00

soroban
Member
Registered: 2007-03-09
Posts: 452

. .

.

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## #23 2011-02-12 07:58:53

soroban
Member
Registered: 2007-03-09
Posts: 452

.

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## #24 2011-02-13 01:06:44

Jai Ganesh
Registered: 2005-06-28
Posts: 47,731

### Re: Algebra

Hi soroban,

I too get the same solutions. Well done!

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #25 2011-03-02 05:54:20

G-man
Member
Registered: 2011-02-28
Posts: 16

Maths!......

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