Solve {l}{4{(5-x)}=25-3{(3x+4)}}{y=20}{text{Solvefor}ztext{where}}{z=y}

$$\left. \begin{array} { l } { 4 {(5 - x)} = 25 - 3 {(3 x + 4)} }\\ { y = 20 }\\ { \text{Solve for } z \text{ where} } \\ { z = y } \end{array} \right.$$

Solve for x, y, z

$$z=20$$

Solution Steps

Consider the first equation. Use the distributive property to multiply 4 by 5-x.

$$20-4x=25-3\left(3x+4\right)$$

Use the distributive property to multiply -3 by 3x+4.

$$20-4x=25-9x-12$$

Subtract 12 from 25 to get 13.

$$20-4x=13-9x$$

Add 9x to both sides.

$$20-4x+9x=13$$

Combine -4x and 9x to get 5x.

$$20+5x=13$$

Subtract 20 from both sides.

$$5x=13-20$$

Subtract 20 from 13 to get -7.

$$5x=-7$$

Divide both sides by 5.

$$x=-\frac{7}{5}$$

The system is now solved.

$$x=-\frac{7}{5} y=20 z=20$$