Substitute and Solve Equations

When solving a system of equations algebraically, which statement results in infinite solutions?

• 4 = 7

• 2 = 2

• -3 = 3

• all of the above

Answer explanation

You will be left with an identity (something true) when trying to solve a system of equations, if there are infinitely many solutions.

Tags

CCSS.8.EE.C.8B

What is the solution to the system?

• (3, -1)

• (2, -6)

• No Solution 

• (6, -2)

Tags

CCSS.8.EE.C.8B

Solve for x and y
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

Solve the system given:
3x - y = 7
2x + y = 3

• (-1,2)

• (5,4)

• (4,5)

• (2,-1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the first step in solving a system by Substitution?

• Make sure both equations are in standard form.

• Make sure at least one equation is solved for one variable.

• Make sure both equations are in slope-intercept form.

• Make sure both equations can be solved.

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

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 Equation (x,y)
–x + 9y = –5
x –5y = 1  

• (-4,-1)

• (4,1)

• (-4,1)

• (1,4)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

How many solutions does this system of equations have?

• One solution

• Infinitely many solutions

• No solutions

• Two solutions

Tags

CCSS.8.EE.C.8B

What is the final step to solve a system with substitution?

• Substitute the values found from the previous step into one of the original equations and solve for the remaining variable

• Solve the linear system for both its variables

• Solve one equation for one of its variables

• Solve one equation for one of its variables

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6