Solve {l}{x+3-4x=12}{y=2x-1}{text{Solvefor}ztext{where}}{z=y}

$$\left. \begin{array} { l } { x + 3 - 4 x = 12 }\\ { y = 2 x - 1 }\\ { \text{Solve for } z \text{ where} } \\ { z = y } \end{array} \right.$$

Solve for x, y, z

$$z=-7$$

Solution Steps

Consider the first equation. Combine x and -4x to get -3x.

$$-3x+3=12$$

Subtract 3 from both sides.

$$-3x=12-3$$

Subtract 3 from 12 to get 9.

$$-3x=9$$

Divide both sides by -3.

$$x=\frac{9}{-3}$$

Divide 9 by -3 to get -3.

$$x=-3$$

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

$$y=2\left(-3\right)-1$$

Multiply 2 and -3 to get -6.

$$y=-6-1$$

Subtract 1 from -6 to get -7.

$$y=-7$$

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

$$z=-7$$

The system is now solved.

$$x=-3 y=-7 z=-7$$