Page 196 - Math Course 2 (Book 1)

Solving Systems of Equations by Multiplying

Your Turn!

Writing Systems of Equations Write and Solve a System of Equations
Susanne has 50 stamps. Two times the number of TRANSPORTATION
f ower stamps plus the number of cartoon stamps A helicopter travels 360 miles with the wind in 3
is 70. Which system of equations can be used hours. The return trip against the wind takes the
to f nd how many f ower stamps f and cartoon helicopter 4 hours. Find the rate of the helicopter in
stamps c she has? still air.

A. f + c = 50 A. 103 mph
f – 2c = 70 B. 105 mph
C. 100 mph
B. f + c = 50 D. 17.5 mph
2f – c = 70
Answer
C. f + c = 50
2f + c = 70

D. f + c = 50
f + 2c = 70

Answer

Skill Practice! Use elimination to solve each system of equations.

1. x + y = –9 2. 3x + 2y = –9
5x – 2y = 32 x – y = –13

3. 2x + 5y = 3 4. 2x + y = 3
–x + 3y = –7 –4x –4y = –8

188