Solve {l}{A={(-20)}-{(-13)}+{(15)}+{(19)}}{a={(-9)}-{({(-11)}+{(8)}-{(12)})}}{text{Solvefor}btext{where}}{b=a}

$$\left. \begin{array} { l } { A = {(-20)} - {(-13)} + {(15)} + {(19)} }\\ { a = {(-9)} - {({(-11)} + {(8)} - {(12)})} }\\ { \text{Solve for } b \text{ where} } \\ { b = a } \end{array} \right.$$

Solve for A, a, b

$$b=6$$

Solution Steps

Consider the first equation. The opposite of -13 is 13.

$$A=-20+13+15+19$$

Add -20 and 13 to get -7.

$$A=-7+15+19$$

Add -7 and 15 to get 8.

$$A=8+19$$

Add 8 and 19 to get 27.

$$A=27$$

Consider the second equation. Add -11 and 8 to get -3.

$$a=-9-\left(-3-12\right)$$

Subtract 12 from -3 to get -15.

$$a=-9-\left(-15\right)$$

The opposite of -15 is 15.

$$a=-9+15$$

Add -9 and 15 to get 6.

$$a=6$$

Consider the third equation. Insert the known values of variables into the equation.

$$b=6$$

The system is now solved.

$$A=27 a=6 b=6$$