How do you solve 3xーy=8 x=5-2y?

1 Answer
Jun 4, 2018

We already know what x equals so we can just use substitution to find what y is equal to; we can then find the value of x using that.

y=-1

x=7

Explanation:

Substitue the equation x=5-2y into the x vairiable of 3x-y=8

3(5-2y)-y=8

15-6y-y=8

15-7y=8

7y=-7

y=-1

We can now substitute the value of y into our original equation

x=5-2(-1)

x=5-(-2)

x=7

So x=7 and y=-1