Systems by Graphing and Substitution

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 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

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

y = -3x + 11

5x + y = 21

• (1, -5)

• (1, 5)

• (-4, 5)

• (5, -4)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

x - 3y = -13

4x + 2y = 4

• (1, 4)

• (-1, -4)

• (-1, 4)

• (1, -4)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

−3x − 3y = 3
y = −5x − 17 

• (-4,3)

• (4,-3)

• (3,-4)

• (-3,-4)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

The solution (x, y) to a system of equations is the set of numbers that make ...?

• All equations false

• At least one equation true

• All equations true

• At least one equation false

Tags

CCSS.8.EE.C.8B

The ordered pair that satisfies BOTH equations in the system is called the _____________________

• system of equations

• function

• graph

• solution 

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the system by substitution. 
-5x - 4y = -9
y = 6

• (3, 6)

• (6, -3)

• (-3, 6)

• (6.8, 3)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6