Question

Solve the system by the substitution method.

X-2y=6
Y=2x-21

Answer 1

`\boxed{x=12, y=3}`

Explanation:

`x-2y=6\\y=2x-21`

Plug y as 2x-21 in the first equation.

`x-2(2x-21)=6\\x-4x+42=6\\-3x+42=6\\-3x=-36\\x=12`

Plug x as 12 in the second equation.

`y=2(12)-21\\y=24-21\\y=3`

Answer 2

Hey there!

We have two equations, x-2y=6, and y=2x-21.

Thus, we can substitute all y's in the first equation for 2x-21.

x-2(2x-21)=6

x-4x+42=6

-3x+42=6

-3x=-36

3x=36

x=12

y=2(12)-21

y=24-21

y=3

x=12, and y=3.

Hope this helps :)