Question

E the system by the method of subs 8x+4y=-2 -12x+5y=-8

Answer 1

x =
`(1)/(4)` , y = - 1

Explanation:

given the equations

8x + 4y = - 2 ( divide through by 2 )

4x + 2y = - 1 ( subtract 2y from both sides )

4x = - 1 - 2y → (1)

- 12x + 5y = - 8 → (2)

substitute 4x = - 1 - 2y into (2) , noting - 12x = - 3(4x)

- 3(- 1 - 2y) + 5y = - 8 ← distribute parenthesis on left side and simplify

3 + 6y + 5y = - 8

3 + 11y = - 8 ( subtract 3 from both sides )

11y = - 11 ( divide both sides by 11 )

y = - 1

substitute y = - 1 into (1) and solve for x

4x = - 1 - 2(- 1) = - 1 + 2 = 1 ( divide both sides by 4 )

x =
`(1)/(4)`

solution is x =
`(1)/(4)` , y = - 1