Question

Solve the system of equations by multiplying. Check the answer by graphing the system of equations.

{
- 4x + 3y = 15
2x +y = -5
The solution is _______?

Answer 1

- 4x + 3y = 15

2x + y = -5

I multiply x 3 the second equality

we will get

- 4x + 3y = 15

6x + 3y = - 15

difference of the 2 equalities

- 4x - 6x + 3y - 3y = 15 - (-15)

- 10x = 30

x = -3

so - 4*(-3) + 3y = 15

3y = 3

y = 1

check

- 4 * (-3) + 3 * 1 = 12 + 3 = 15