Solve {l}{x=-5}{y=5}{z=4xy-x^3}{text{Solvefor}atext{where}}{a=z}

$$\left. \begin{array} { l } { x = -5 }\\ { y = 5 }\\ { z = 4 x y - x ^ {3} }\\ { \text{Solve for } a \text{ where} } \\ { a = z } \end{array} \right.$$

Solve for x, y, z, a

$$a=25$$

Solution Steps

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

$$z=4\left(-5\right)\times 5-\left(-5\right)^{3}$$

Multiply 4 and -5 to get -20.

$$z=-20\times 5-\left(-5\right)^{3}$$

Multiply -20 and 5 to get -100.

$$z=-100-\left(-5\right)^{3}$$

Calculate -5 to the power of 3 and get -125.

$$z=-100-\left(-125\right)$$

Multiply -1 and -125 to get 125.

$$z=-100+125$$

Add -100 and 125 to get 25.

$$z=25$$

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

$$a=25$$

The system is now solved.

$$x=-5 y=5 z=25 a=25$$