Solve {l}{4+5y=15}{x+yy=20}

$$\left. \begin{array} { l } { 4 + 5 y = 15 } \\ { x + y y = 20 } \end{array} \right.$$

Solve for y, x

$$x = \frac{379}{25} = 15\frac{4}{25} = 15.16$$

$$y = \frac{11}{5} = 2\frac{1}{5} = 2.2$$

Solution Steps

Consider the first equation. Subtract 4 from both sides.

$$5y=15-4$$

Subtract 4 from 15 to get 11.

$$5y=11$$

Divide both sides by 5.

$$y=\frac{11}{5}$$

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

$$x+\frac{11}{5}\times \frac{11}{5}=20$$

Multiply \frac{11}{5} and \frac{11}{5} to get \frac{121}{25}.

$$x+\frac{121}{25}=20$$

Subtract \frac{121}{25} from both sides.

$$x=20-\frac{121}{25}$$

Subtract \frac{121}{25} from 20 to get \frac{379}{25}.

$$x=\frac{379}{25}$$

The system is now solved.

$$y=\frac{11}{5} x=\frac{379}{25}$$