Making a decision … Now that you know 3 ways to solve a system of equations, how to choose which method to use when solving systems of equations.

Two angles are supplementary. The measure of one angle is 10 degrees more than three times the other. Find the measure of each angle.

Two angles are supplementary. The measure of one angle is 10 more than three times the other. Find the measure of each angle. x = degree measure of angle #1 y = degree measure of angle #2 Therefore x + y = 180

Two angles are supplementary. The measure of one angle is 10 more than three times the other. Find the measure of each angle. x + y = 180 x =10 + 3y

Solve x + y = 180 x =10 + 3y x + y = 180 -(x - 3y = 10) 4y =170 y = 42.5 x = 180 x = x = (137.5, 42.5)

The sum of two numbers is 70 and their difference is 24. Find the two numbers.

x = first number y = second number Therefore, x + y = 70

The sum of two numbers is 70 and their difference is 24. Find the two numbers. x + y = 70 x – y = 24

x + y =70 x - y = 24 2x = 94 x = y = 70 y = 70 – 47 y = 23 (47, 23)

Solve 1.Find two numbers whose sum is 18 and whose difference is The sum of two numbers is 128 and their difference is 114. Find the numbers.