Question

Hello! Can someone help me with a substitution problem? Pre-Alg level.

3x+9y=42
y=2x

Answer 1

x=2

Explanation:

The equation becomes 3x+9(2x)=42. Then you distribute the 9 into the 2x. Combine 3x and 18x for 21x=42. Divide 21 by both sides and you get x=2.