Question

Using the linear combaination method what is the solution to the system of linear equations 7x-2y=-20and9x+4y=-6

Answer 1

x=-2 y=3

Explanation:

7x-2y=-20

9x+4y=-6

Multiply the first equation by 2

2(7x-2y) = 2 * -20

14x - 4y = -20

Add this to the second equation

14x - 4y = -40

9x+4y=-6

--------------------------

23x = -46

Divide by 23

23x/23 = -46/23

x = -2

Now we solve for y

9x+4y=-6

9(-2) +4y = -6

-18 + 4y = -6

Add 18 to each side

-18+18 +4y = -6+18

4y = 12

Divide by 4

4y/4 = 12/4

y=3