Question

Explain, in complete sentences, how you would use the elimination method to solve the following system of equations. Provide the solution to the system.

6x – 5y = 4
9x + 4y = –17

Thanks !

Answer 1

kelliegirl13, you got this? :)

Answer 2

The elimination method requires you to " eliminate " either the x's or the y's to find the other letter. To do this, you sometimes have to multiply one or both of the equations by a number so that the x's or the y's cancel each other out.
We will begin now...
6x - 5y = 4 --->(4)6x - 5y = 4
9x + 4y = - 17 -->(5) 9x + 4y = - 17
--------------
24x - 20y = 16 (result of multiplying by 4)
45x + 20y = - 85 (result of multiplying by 5)
---------------add
69x + 0 = - 69
69x = - 69
x = -69/69 = - 1
we have found x, so now we must substitute -1 in for x in either of the original equations.
6x - 5y = 4
6(-1) - 5y = 4
-6 - 5y = 4
-5y = 4 + 6
-5y = 10
y = 10/-5 = -2
lets check our answers now...
9x + 4y = - 17
9(-1) + 4(-2) = -17
-9 - 8 = - 17
-17 = -17 (correct)
ANSWER: x = -1 and y = -2 or (-1,-2)
Any questions ?

Answer 3

Nope, i'm good! Thanks!

Answer 4

good to hear...glad I could help :)