Solve {l}{3a+2x=17}{x-y=4}

$$\left\{ \begin{array} { l } { 3 a + 2 x = 17 } \\ { x - y = 4 } \end{array} \right.$$

Solve for x, y

$$x=\frac{17-3a}{2}$$

$$y=\frac{9-3a}{2}$$

Steps Using Substitution

To solve a pair of equations using substitution, first solve one of the equations for one of the variables. Then substitute the result for that variable in the other equation.

$$2x+3a=17,x-y=4$$

Pick one of the two equations which is more simple to solve for x by isolating x on the left hand side of the equal sign.

$$2x+3a=17$$

Subtract 3a from both sides of the equation.

$$2x=17-3a$$

Divide both sides by 2.

$$x=\frac{17-3a}{2}$$

Substitute \frac{17-3a}{2} for x in the other equation, x-y=4.

$$\frac{17-3a}{2}-y=4$$

Subtract \frac{17-3a}{2} from both sides of the equation.

$$-y=\frac{3a-9}{2}$$

Divide both sides by -1.

$$y=\frac{9-3a}{2}$$

The system is now solved.

$$x=\frac{17-3a}{2},y=\frac{9-3a}{2}$$