System of Equations Review

Elizabeth needs to solve the system of equations below.
-2x + y =14
3x + 2y =7
She decides to use the elimination method to cancel out the y terms in order to first solve for x. Elizabeth uses the following steps:
Step 1: 

-2 (-2x + y)= 14


Step 2:
4x -2y = 14
3x +2y =7

Step 3:
7x=21

Step 4:

x= 3

• Yes, Elizabeth correctly solved for x.

• No, Elizabeth should have multiplied the second equation by -2.

• No, Elizabeth should have multiplied the entire first equation by -2.

• No, Elizabeth should have multiplied the entire second equation by -1.

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Plot the system of equations to estimate the intersection point of the two lines. Use graph paper.

 $y=\frac{1}{4}x-4$  

 $y=-\ \frac{1}{2}x-1$ 

• (4,3)

• (4,-3)

• (-4,3)

• (-4,-3)

Tags

CCSS.8.EE.C.8B

 $16x-10y=10$  

 $-8x-6y=6$  

Solve the system of equations.

• (0,1)

• (0,-1)

• (1,0)

• (-1,0)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

 $x=-3y+4$  
 $6y\ +2x=8$  
Identify the solution to the system of equations.

• (2,3)

• no solution

• infinitely many

• none of the above

Tags

CCSS.8.EE.C.8B

Where do the lines defined by the following intersect?

x+ y = 8

y = 3x

• (2, -6)

• (-2, -6)

• (-2, 6)

• (2, 6)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Give the x= and y= for the following equations:

2x + 5y = 17

6x - 5y = -9

• x= -1

  y= 3

• x= 1

  y= 3

• x= 1

  y= -3

• x= -1

  y= -3

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Izzy works in a food truck, they sell drinks and candy.

• She sells 2 drinks and 3 candies for 9 dollars.
• She sells 1 drink and 5 candies for 8 dollars.

This situation can be modeled by the system of equations shown below.

2d + 3c= 9

d+5c = 8

Then Izzy sells 3 drinks and 4 candies. What is the total cost of this order?

• $15.00

• $4.00

• $11.00

• $13.00

Tags

CCSS.8.EE.C.8C