Question

3. Solve the system of equations:
y = 7x+10
y = -4x - 23

Answer 1

`x = - 3, y = - 11`

Explanation:

Given the 2 equations

`y = 7x + 10` → (1)

`y = - 4x - 23` → (2)

Substitute
`y = 7x + 10` into (2)

`7x + 10 = - 4x - 23` ( add 4x to both sides )

`11x + 10 = - 23` ( subtract 10 from both sides )

`11x = - 33` ( divide both sides by 11 )

`x = - 3`

Substitute
`x = - 3` into either of the 2 equations and evaluate for y

Substituting into (1)

`y = 7(- 3) + 10 = - 21 + 10 = -11`