Solving Systems by Elimination

Macy starts with $20 in her bank account and she saves $5 each week. Robby has $100 in his bank account, and he saves $2.50 each week. After how many weeks will Macy and Robby have the same amount in their accounts and how much money will that be? Write a system of equations to solve.

• 25 weeks; $160

• 32 weeks; $180

• 20 weeks; $120

• 22 weeks; $135

Ride and Transport are two new ride sharing companies in Colorado. Ride is charging $2 for pick up fees and then $2.50 per mile. Transport is charging only $2.70 per mile. How many miles will it take for both companies to charge the same amount? Write a system of equations to solve.

• 27 miles

• 10 miles

• 270 miles

• 100 miles

Solve by elimination:
7x+y=-9

-3x-y=5

• No solution

• (1,8)

• (-2,-3)

• (-1,-2)

Solve by elimination:
9x-4y=7

x-4y=-17

• (-1,5)

• (-7,5)

• (7,5)

• (3,5)

Solve by elimination
4x-6y= -6
-2x-12y= -12

• (0,1) 

• (1,0)

• (1,1)

• (2,1)

Solve by elimination:
3x+7y=23

-3x-7y=-17

• No solution

• ARN

• (-3,3)

• (3,3)

Solve by elimination:
-9x-4y=-20

5x+4y=4

• (-4,4)

• (4,4)

• (4,-4)

• (-4,-4)

Solve by elimination:
4x+4y=4

3x+4y=10

• (7,-6)

• (-6,7)

• (6,7)

• (7,6)

Solve by elimination:
7x-9y=29

7x+2y=-15

• (-4,-1)

• (-1.-4)

• (-1,4)

• (-1,6)

Solve by elimination 
-12x-10y= 0 
 6x+5y= -1

• infinite solutions

• (0,0)

• no solution 

• (2,1)