Solve system of equations by substitutions

If a system of equations has no solution, what does the graph look like? 

• intersecting lines
• parallel lines
• same lines

Tags

CCSS.8.EE.C.8A

If the solution is infinitely many the lines will ________?

• intersect at exactly one point
• be parallel
• overlap each other
• never exist

Tags

CCSS.8.EE.C.8A

Solve the system by substitution. 
y = 2x − 11 
2x − 8y = 4 

•  (6, 1)
• (6, −4)
• (6, −1)
• Infinite number of solutions  

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the system by substitution. 
3x − 2y = 7 
y = 2x − 7 

• No solution 
•  (7, 7)  
•  (−7, −7)  
•  (−7, −3)  

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

The solution (x, y) to a system of equations is the point where they...? 

• Run off the graph
• Don't touch
• Intersect
• Exist

Tags

CCSS.8.EE.C.8B

Solve the following system:

 $-7x-2y=-13$  

 $x=2y+11$  

•  $\left(3,\ -4\right)$  

•  $\left(3,\ 4\right)$  

•  $\left(-3,\ -4\right)$  

•  $\left(-3,\ 4\right)$  

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

Solve the system by substitution.
 
5x + 4y= −14
y =  −7x  −  15 

• (-2, -1)
• (1, -2)
• (-2, 1)
• (-1, -2)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve:
y = 2x -11
-3y = -6x -15

• (-1.5,-4)
• (1.5,4)
• No solution (parallel lines)
• Infinitely many solutions

Tags

CCSS.8.EE.C.8B

x + 2y = 2
x = -4y + 2

• (-3, 0)
• (0, 2)
• (-3, -2)
• (2, 0)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6