Question

Solve the system of linear equations by elimination. Write your answer in the form (x,y)

-7x-8y=9
-4x+9y=-22

Answer 1

Solution: (1,-2)

Explanation:

System of Equations

Given the equations:

`-7x-8y=9\qquad\qquad [1]`

`-4x+9y=-22\qquad\qquad [2]`

We'll solve it by elimination. It means eliminating one of the variables by equating their coefficients. We select the variable y. To eliminate it, multiply the equation [1] by 9 and the equation[2] by 8:

-63x-72y=81

-32x+72y=-176

Adding up both equations:

-95x=-95

Solving:

x=-95/(-95)=1

x=1

Now to eliminate x and find y, multiply [1] by 4 and [2] by -7:

-28x-32y=36

28x-63y=154

Adding up both equations:

-95y=190

Solving:

y=190 / (-95) = -2

y=-2

Solution: (1,-2)