x=7-2y and 2x+y=5 Substitution

Question

Algebra 1 Substitution.

Answer 1

You're told in the first equation that x = 7 - 2y.

In the second equation, instead of using x, use 7-2y. So your new equation is 2(7 - 2y) + y = 5.

Now you can solve the equation for y. Distribute the 2(7 - 2y). You get 14 - 4y.

14 - 4y + y = 5.

Combine like terms: 14 - 3y = 5.

Subtract 14 from both sides. -3y = -9

Divide both sides by -3: y = 3

Now that you know what y is, you can substitute 3 for y in either equation: x = 7 - 2(3)

x = 7-6

x = 1

x = 1 and y = 3