Solve {l}{21x+124=84-11}{7x+4y=28-6}

$$\left. \begin{array} { l } { 21 x + 124 = 84 - 11 } \\ { 7 x + 4 y = 28 - 6 } \end{array} \right.$$

Solve for x, y

$$x = -\frac{17}{7} = -2\frac{3}{7} \approx -2.428571429$$

$$y = \frac{39}{4} = 9\frac{3}{4} = 9.75$$

Solution Steps

Consider the first equation. Subtract 11 from 84 to get 73.

$$21x+124=73$$

Subtract 124 from both sides.

$$21x=73-124$$

Subtract 124 from 73 to get -51.

$$21x=-51$$

Divide both sides by 21.

$$x=\frac{-51}{21}$$

Reduce the fraction \frac{-51}{21} to lowest terms by extracting and canceling out 3.

$$x=-\frac{17}{7}$$

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

$$7\left(-\frac{17}{7}\right)+4y=28-6$$

Multiply 7 and -\frac{17}{7} to get -17.

$$-17+4y=28-6$$

Subtract 6 from 28 to get 22.

$$-17+4y=22$$

Add 17 to both sides.

$$4y=22+17$$

Add 22 and 17 to get 39.

$$4y=39$$

Divide both sides by 4.

$$y=\frac{39}{4}$$

The system is now solved.

$$x=-\frac{17}{7} y=\frac{39}{4}$$