Question

How do you solve the following system?: `2x+3y=-5 , y=2x+9`

Answer 1

`x=-4, y=1`

Explanation:

1. `2x+3y =-5`
2. `y=2x+9`

Equation 2 already has `y` as the subject of the equation, substitute that in place of the `y` in the first equation.

`2x + 3(2x+9) = -5`

Simplify the equation and calculate the value of `x`.

`2x+6x+27 = -5`
`8x = -32`
`x=-4`

Then insert that value of `x` into equation 2 to find the value of `y`.

`y=2(-4)+9`
`y=-8+9`
`y=1`