Solve left(x+3right)^2-x(x+2)=3x+1

$${ \left(x+3 \right) }^{ 2 } -x(x+2)=3x+1$$

Solve for x

$$x=-8$$

Steps for Solving Linear Equation

Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(x+3\right)^{2}.

$$x^{2}+6x+9-x\left(x+2\right)=3x+1$$

Use the distributive property to multiply x by x+2.

$$x^{2}+6x+9-\left(x^{2}+2x\right)=3x+1$$

To find the opposite of x^{2}+2x, find the opposite of each term.

$$x^{2}+6x+9-x^{2}-2x=3x+1$$

Combine x^{2} and -x^{2} to get 0.

$$6x+9-2x=3x+1$$

Combine 6x and -2x to get 4x.

$$4x+9=3x+1$$

Subtract 3x from both sides.

$$4x+9-3x=1$$

Combine 4x and -3x to get x.

$$x+9=1$$

Subtract 9 from both sides.

$$x=1-9$$

Subtract 9 from 1 to get -8.

$$x=-8$$