Solve {l}{x-9=19-3x}{x-a=10quad2x}

$$\left. \begin{array} { l } { x - 9 = 19 - 3 x } \\ { x - a = 10 \quad 2 x } \end{array} \right.$$

Solve for x, a

$$x=7$$

$$a=-133$$

Solution Steps

Consider the first equation. Add 3x to both sides.

$$x-9+3x=19$$

Combine x and 3x to get 4x.

$$4x-9=19$$

Add 9 to both sides.

$$4x=19+9$$

Add 19 and 9 to get 28.

$$4x=28$$

Divide both sides by 4.

$$x=\frac{28}{4}$$

Divide 28 by 4 to get 7.

$$x=7$$

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

$$7-a=10\times 2\times 7$$

Multiply 10 and 2 to get 20.

$$7-a=20\times 7$$

Multiply 20 and 7 to get 140.

$$7-a=140$$

Subtract 7 from both sides.

$$-a=140-7$$

Subtract 7 from 140 to get 133.

$$-a=133$$

Divide both sides by -1.

$$a=-133$$

The system is now solved.

$$x=7 a=-133$$