Graphing and Using Substitution for Systems

Solve this system of equations by graphing.

y = 4x - 2

y = -x + 3

• (-2,-1)

• (-1,-2)

• (1,2)

• (2,1)

Tags

CCSS.8.EE.C.8B

What is the solution to this system?

• (-2, -2)

• (2, -2)

• (-2,2)

• (2, 2)

Tags

CCSS.8.EE.C.8B

Which variable should you isolate first in the system?

• The x in the first equation

• The y in the first equation

• The y in the second equation

• The x in the second equation

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve with substitution

x = -3y - 8

x - 2y = -3

• (5, -1)

• (-5, 1)

• (-5,-1)

• (1,-5)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the system by substitution

3x - y = 4

x + 2y = 6

• (-2, 2)

• (2, -2)

• (2, 2)

• (-2, -2)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the best method do you use?

x = 6y − 11

−2x − 3y = −7

• Graphing, because they are both in slope-intercept form

• Substitution because a variable is isolated (solved for)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the best method to use?

y = −3x + 5

y = x -1

• Graphing, because they are both in slope-intercept form

• Substitution because a variable is isolated (solved for)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

The first step in solving using the substitution method is __________.

• get x by itself

• get y by itself

• get either variable by itself

• add the equations together

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the system:
x + y = 19
y = 3x - 1

• (14, 5)

• (11, 8)

• (5, 14)

• (8, 11)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the system:
3x + y = 19
2x - y = 6

• (5, 14)

• (4, 5)

• (5, 4)

• (14, 5)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6