Question

How do you solve `2x+9y=17`, `x=7-4y`?

Answer 1

x= -5
y= 3

Explanation:

Generally, you can solve linear systems in different ways:

1) Graphing

2) Substitution

3) Elimination.

In this case, since x is already isolated in the second equation, we would use substitution.

`2x + 9y = 17` Then we substitute `x = 7-4y`

`2(7-4y) + 9y = 17`

`14-8y + 9y = 17`

`y=3`

Then solve for x using either equation (I picked the second one)

`x = 7 - 4y`
`x = 7 - 4(3)`
`x = -5`