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#1 2006-10-31 04:46:06

unique
Member
Registered: 2006-10-04
Posts: 419

correct

write the equation for the line that passes through the point (2,4) and is parallel to the line
y = 2x + 5

now this problem that i found on net is almost as same as my problem . can i do the same way that they did for this problem. not teh same way but still. hmm

Find an equation of the line that passes through the point (-2 , 3) and is parallel to the line 4x + 4y = 8

Let m1 be the slope of the line whose equation is to be found and m2 the slope of the given line. Rewrite the given equation in slope intercept form and find its slope.
4y = -4x + 8
Divide both sides by 4
y = -x + 2
slope m2 = -1.
Two lines are parallel if and only if they have equal slopes
m1 = m2 = -1
We now use the point slope form to find the equation of the line with slope m1.
y - 3 = -1(x - (-2))
which may be written as
y = -x + 1


Desi
Raat Key Rani !

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#2 2006-10-31 04:58:18

polylog
Member
Registered: 2006-09-28
Posts: 162

Re: correct

Yes you can do your question like that too -- except you can see the slope of your line is 2 already, without re-writing it. The key thing to know is: parallel lines have the exact same slope.

So your parallel line's equation will be y = 2x + b  ... now you just need to find b. But you know a point on the line, so just substitute the point in this equation!

Last edited by polylog (2006-10-31 04:59:19)

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