Solve {l}{x/990=8.89}{x/850-y=9.9}

$$\left. \begin{array} { l } { \frac { x } { 990 } = 8.89 } \\ { \frac { x } { 850 - y } = 9.9 } \end{array} \right.$$

Solve for x, y

$$x=8801.1$$

$$y=-39$$

Solution Steps

Consider the first equation. Multiply both sides by 990.

$$x=8.89\times 990$$

Multiply 8.89 and 990 to get 8801.1.

$$x=8801.1$$

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

$$\frac{8801.1}{850-y}=9.9$$

Variable y cannot be equal to 850 since division by zero is not defined. Multiply both sides of the equation by -y+850.

$$8801.1=9.9\left(-y+850\right)$$

Use the distributive property to multiply 9.9 by -y+850.

$$8801.1=-9.9y+8415$$

Swap sides so that all variable terms are on the left hand side.

$$-9.9y+8415=8801.1$$

Subtract 8415 from both sides.

$$-9.9y=8801.1-8415$$

Subtract 8415 from 8801.1 to get 386.1.

$$-9.9y=386.1$$

Divide both sides by -9.9.

$$y=\frac{386.1}{-9.9}$$

Expand \frac{386.1}{-9.9} by multiplying both numerator and the denominator by 10.

$$y=\frac{3861}{-99}$$

Divide 3861 by -99 to get -39.

$$y=-39$$

The system is now solved.

$$x=8801.1 y=-39$$