a) $$\boxed{2}+4=6$$

b) $$\boxed{12}-4=8$$

c) $$4+\boxed{-1}-2=1$$

d) $$3-7+\boxed{14}=10$$

e) $$3-\boxed{-9}=12$$

a) $$2·\boxed{3}+2=8$$

b) $$3·\boxed{3}-3=6$$

c) $$7·\boxed{-1}-3=-10$$

d) $$6+3·\boxed{-2}=0$$

e) $$-3·\boxed{-1}-3=0$$

a)

$$\begin{array}{rcl}x& = & 5+1\\ & & \\ x& =& 6\end{array}$$

b)

$$\begin{array}{rcl}5x& = & 12-2\\ & & \\ 5x& =& 10\\ & & \\ \frac{\cancel{5}x}{\cancel{5}}& =& \frac{10}{5}\\ & & \\ x& =& 2\end{array}$$

c)

$$\begin{array}{rcl}5x& = & 25+5\\ & & \\ 5x& =& 30\\ & & \\ \frac{\cancel{5}x}{\cancel{5}}& =& \frac{30}{5}\\ & & \\ x& =& 6\end{array}$$

d)

$$\begin{array}{rcl}-3x& = & -2-4\\ & & \\ -3x& =& -6\\ & & \\ \frac{\cancel{-3}x}{\cancel{-3}}& =& \frac{-6}{-3}\\ & & \\ x& =& 2\end{array}$$

e)

$$\begin{array}{rcl}6x& = & 22+2\\ & & \\ 6x& =& 24\\ & & \\ \frac{\cancel{6}x}{\cancel{6}}& =& \frac{24}{6}\\ & & \\ x& =& 4\end{array}$$

a)

$$\begin{array}{rcl}2(x-2)& = & 8\\ & & \\ 2x-4& =& 8\\ & & \\ 2x& =& 12\\ & & \\ x& =& 6\end{array}$$

b)

$$\begin{array}{rcl}3x-x& = & 12-6\\ & & \\ 2x& =& 6\\ & & \\ x& =& 3\end{array}$$

c)

$$\begin{array}{rcl}\frac{x}{3}-\frac{1}{3}& = & \frac{4}{3}\\ & & \\ x-1& =& 4\\ & & \\ x& =& 5\end{array}$$

d)

$$\begin{array}{rcl}\frac{5}{\cancel{x}}·2\cancel{x}-\frac{1}{\cancel{2}}·\cancel{2}x& = & 2·2x\\ & & \\ 10-x& =& 4x\\ & & \\ -x-4x& =& -10\\ & & \\ -5x& =& -10\\ & & \\ \frac{\cancel{-5}{\displaystyle x}}{\cancel{-5}}& =& \frac{-10}{-5}\\ & & \\ x& =& 2\end{array}$$

e)

$$\begin{array}{rcl}2\left(x-3\right)& = & -3\left(x+4\right)\\ & & \\ 2x-6& =& -3x-12\\ & & \\ 5x& =& -6\\ & & \\ x& =& -\frac{6}{5}\end{array}$$

a)

$$\begin{array}{rcl}{x}^2& = & 12-8\\ & & \\ x^2& =& 4\\ & & \\ x& =& \pm \sqrt{4}\\ & & \\ x& =& \pm 2\end{array}$$

b)

$$\begin{array}{rcl}4x^2& = & 70-6\\ & & \\ 4x^2& =& 64\\ & & \\ \frac{\cancel{4}{x}^2}{\cancel{4}}& =& \frac{64}{4}\\ & & \\ x^2& =& 16\\ & & \\ x& =& \pm \sqrt{16}\\ & & \\ x& =& \pm 4\end{array}$$

c)

$$\begin{array}{rcl}-x^2+2 & = & 2x^2-25\\ & & \\ 3x^2& =& 27\\ & & \\ x^2& =& 9\\ & & \\ x& =& \pm 3\end{array}$$