Math Is Fun Forum

Hi guys!!!

1)
how would I find the gradient and y-intercept of the line when the y line starts from o to 1 to 2 to 3 and from 0 to  -1 to -2  to -3.

The x line goes  from 0 to 2 to 4 to 6 to 8 and from 0 to -2 to -4 to -6 to -8.
A line passes through 4 on the x line and -1 on the y line.??????

after this once the gradient and y-intercept has been found how would I write the equation of the line that passes through 4 on the x line and -1 on the y line

2)
a)  how would I find the gradients of each of these lines

i)   y = 3x + 12

ii)  2y - 6x = 2

b)  why do these lines not have a point of intersection? how would I justify this answer??

all this is making my head spin

There are 4 people in my family who contribute to repayments. A, B and C contribute 60 percent of their weekly income and D contributes 25 percent of his weekly income to monthly repayments. A makes $720 per week. B earns $690 per week. C earns $820 per week.
We have taken out a $560 000 loan at 6.4% over a 30 year period.

a) what amount will I have to repay each month?

b) how much will I have to repay in total on this loan?

c) is there any way of working out how long it will take to pay off the mortgage if we increase the monthly repayments by 10% after 5 years of my 30 year loan period, and how much extra do we individually have to put in?

1) can anyone please explain in words and perhaps even diagrams how I would go about working out this solution, and
2) can anyone please show me the mathematical steps involved in answering this question?

In calculating how much of a certain medicine to give to a child, a formula called Clark's rule is sometimes used.

C = wa/70               where C represents the dosage required for the child,  w represents the
                               weight of the child in kg, and a represents the adult dosage.

a)    Find the dosage for a given medicine for a 20 kg child, where the adult dosage was 15mL.
   
b)   Calculate the adult dose if you know that a 40 kg child recieved 8 mL.

Thanks so very much this makes so much of a difference helping my young child with her homework. Never quite completed high school maths and feel so silly when trying to help my child out so having some idea with the "how" provided by you wonderful people makes a significant difference

More help requested

An algebraic model for the hieght of women based on their weight is described by a formula. The formula states, to find the hieght of a women in cm, multiply her weight in kg by 2.1 and then add 40.

a)  write this formula and define any varibales that you have used?

b)  Use your formula to predict the hieghts of the women missing in the floowing table:

    weight kg     height cm
      57                 159.7
      59                  163.9
     61
     69

can anyone helpme with this:

At the local sale yard some years ago, one farmer bought a group of 6 horses and 7 cows for $2 500. Another farmer bought a group of 13 cows and 1 horse for $2 310. If C is the cost in dollars of 1 cow and H is the cost in dollars of 1 horse:

a)  write 2 equations that relate the number of horses and cows to their costs?

b) solve the above equations simultaneoulsy to find the cost of a cow and the cost of a horse?

c)  how would you check that solution is correct?