52.2k views
1 vote
Solve this system of linear equations. Separate the x- and y-values with a comma. -7x + 2y = -8 -16x + 9y = 26

1 Answer

3 votes
(4,10).
1. There are three ways to solve this: elimination, substitution, graphing.
2. I chose elimination, so I had to get one negative variable and one positive variable of the same value (for example, 18 and -18)

-7x+2y=-8
-16x+9y=26
I chose to get 2y and 9y to equal -18y and 18y.
So, multiply the first equation by -9. Multiply the second by 2.
63x-18y=72
-32x+18y=52
the 18s cross each other out. So you're left with
63x=72
-32x=52. Add them.
31x=124, divide both sides by 31, and you'll get 4.
x=4
Plug your answer for x into one of the equations. Let's use the first one.
-7(4)+2y=-8
-28+2y=-8. add 28 to both sides.
2y=20, divide both sides by 2.
y=10.
This makes your answer (4,10)
User Bastian Stein
by
8.6k points