### Home > CC3 > Chapter 3 > Lesson 3.2.1 > Problem3-74

3-74.

For the following equations, solve for $x$. Be sure to check your answer, if possible. Show all work. Homework Help ✎

1. $3x+7=−x−1$

Subtract $7$ from both sides.

$3x+7=−x−1$
$−7\ \ \ \ \ \ \ \ \ \ \ \ −7$

Get the variable on a side by itself.

$3x=−x−8$
$+x\ \ \ \ \ +x$
$4x=−8$

Solve for $x$.

$x=−2$

1. $−3x=x−(6−2x)$

Follow the steps in part (a).

How does the negative sign in front of the parentheses change what is inside?

1. Use a diagram of the Equation Mat or some other method to explain why $−(x−3)=−x+3$.

Refer to the Math Notes box in Lesson 2.1.9 if you need more help with using an Equation Mat.