### Home > CCAA8 > Chapter 4 Unit 5 > Lesson CCA: 4.2.1 > Problem4-40

4-40.

Kevin and his little sister, Katy, are trying to solve the system of equations shown below. Kevin thinks the new equation should be $3(6x−1)+2y=43$, while Katy thinks it should be $3x+2(6x−1)=43$. Who is correct and why?

$y=6x−1$
$3x+2y=43$

In order to solve the system of equations $6x−1$ must be substituted in for $y$.

$3x+2(6x−1)=43$

Katy is right.