Solving Systems with Substitution

Which is the best method to use?

y = 6x − 11

−2x − 3y = −7

• Graphing

• Substitution because a variable is isolated.

• Elimination because both equations are in standard form.

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the system of equations. x + 2y = -3

y = x + 12

• (-9, 3)

• (-7 ,5)

• (3, 15)

• (9, 6)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the following system using any method.

y=-x+4

y=2x+4

• (0,4)

• (2,4)

• (-1,3)

• (4,0)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Find the solution to the system of equations:
3x + 2y = 16
y = -7x + 19

• (-2,5)

• (-2,-5)

• (2,-5)

• (2,5)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Determine if (4, 1) is a solution for the system of equations.
y = -x + 5
y = 2x - 7

• yes

• no

Which answer has a correct first step for solving this system without graphing:

• The variable is already isolated, so we've already solved the system.

• The variable is already isolated for y, so we substitute it in the first equation and solve for x

  3x + 3(3x + 5) = 3

• Free sha vaca doo

• The variable is already isolated for y, so we substitute it in the second equation and solve for x

  y = 3(3x + 3y) = 3

Answer explanation

$3x+3y=3$

$y=3x+5$
A variable is already isolated here, so we already have an equivalent expression from the second equation that can be substituted in place of y in the first equation.

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the solution to this system?
x= 7 - 2y
2x + y = 5

• (-1,4)

• (4,-1)

• (1,3)

• (3,1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

The equations of two lines are:

2x-y=4 and y=-2x+8.

What is the value of x in the solution for this system?

• x=8

• x=3

• x=11

• x=5

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the solution to this system?
y= 4x + 3
2x - 3y = 21

• (3,-9)

• (-3,-9)

• (-3,9)

• (0,1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the solution to this system?
y = 2x + 1
y = 4x - 1

• (1,3)

• (-1,-3)

• (-1,3)

• (3,1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6