### Home > CC3 > Chapter 3 > Lesson 3.1.7 > Problem3-68

3-68.

Paris is trying to solve the equation $3x^2−(2x−4)=3+3x^2+1$. Her work is partially recorded below. Copy her table and fill in her missing work to solve for $x$.

Left Expression

Right Expression

Explanation

$3x^2-(2x-4)$

$3+3x^2+1$

Starting expressions.

$3x^2-2x+4$

$3+3x^2+1$

Remove $3x^2$ from both sides.

$-2x$

$0$

Divide both sides by $-2$.

To figure out what comes next in the equation, notice what changes in each step and make sure to

Left Expression

Right Expression

Explanation

$3x^2-(2x-4)$

$3+3x^2+1$

Starting expressions.

$3x^2-2x+4$

$3+3x^2+1$

$\color{red}{\text{Flip tiles from "-" region to "+" region.}}$

$\color{red}{-2x+4}$

$\color{red}{3+1}$

Remove $3x^2$ from both sides.

$-2x$

$0$

$\color{red}{\text{Take 4 away from both sides.}}$

Divide both sides by $-2$.