I need help on a question the questions says

by eliminating Y, find the solution to the Simulataneous Eqautions.

X(squared)+Y(squared)=25

Y=X-7

Thanks in Advance,

Aslam

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- May 16th 2009, 11:57 AMAslam AnjumBasic Math Problem
I need help on a question the questions says

by eliminating Y, find the solution to the Simulataneous Eqautions.

X(squared)+Y(squared)=25

Y=X-7

Thanks in Advance,

Aslam - May 16th 2009, 11:59 AMartvandalay11
Plug x-7 in for y in the first equation so $\displaystyle x^2+(x-7)^2=25$

- May 16th 2009, 12:00 PMe^(i*pi)
- May 16th 2009, 12:08 PMAslam Anjum
Thanks for that but I think this is a quadratic as there is space to put two sets of values for X and Y.

can you please work it out and tell what the answers are so i can check to see if I'm gettting the right answers

Thanks again,

Aslam - May 16th 2009, 12:16 PMartvandalay11
You can tell us what you get for answers and we'll tell you if you are right. This forum is to help people not to do it for you

- May 16th 2009, 12:22 PMe^(i*pi)
Well you can solve that equation to find x and from there find y:

$\displaystyle 2x^2 - 14x + 24 = 0$

Divide by 2: $\displaystyle x^2 - 7x+12 = 0$

I can see that this factorises to $\displaystyle (x-4)(x-3) = 0$

therefore either x-4=0 or x-3=0 and therefore x = 4 or x=3.

We then put these back into y = x-7

y = 4-7 = -3 or y = 3-7 = -3.

Our solutions are therefore x=4, y=-3 or x=3, y=-4. There are two pairs of answers for this - May 16th 2009, 12:48 PMAslam Anjum
thanks for that i didnt get anything close to that I started using the other eqaution i cant tell which equation to use when i see the questions.

thanks for the help,

Aslam