Solve {l}{-12+2y+4=-21+y}{=9-13y-2=-6-a}

$$\left. \begin{array} { l } { - 12 + 2 y + 4 = - 21 + y } \\ { = 9 - 13 y - 2 = - 6 - a } \end{array} \right.$$

Solve for y, a

$$y=-13$$

$$a=-182$$

Solution Steps

Consider the first equation. Add -12 and 4 to get -8.

$$-8+2y=-21+y$$

Subtract y from both sides.

$$-8+2y-y=-21$$

Combine 2y and -y to get y.

$$-8+y=-21$$

Add 8 to both sides.

$$y=-21+8$$

Add -21 and 8 to get -13.

$$y=-13$$

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

$$9-13\left(-13\right)-2=-6-a$$

Multiply -13 and -13 to get 169.

$$9+169-2=-6-a$$

Add 9 and 169 to get 178.

$$178-2=-6-a$$

Subtract 2 from 178 to get 176.

$$176=-6-a$$

Swap sides so that all variable terms are on the left hand side.

$$-6-a=176$$

Add 6 to both sides.

$$-a=176+6$$

Add 176 and 6 to get 182.

$$-a=182$$

Divide both sides by -1.

$$a=-182$$

The system is now solved.

$$y=-13 a=-182$$