October 8th Warm-Up

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

• intersecting lines
• parallel lines
• skew lines
• intersecting lines

Tags

CCSS.8.EE.C.8A

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

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

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 of equations using substitution:
y = 2x + 5
2x + 2y = 4

• (1, 7)
• (7, 1)
• (2, 9)
• (-1, 3)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the value of the y-coordinate of the solution to the system of equations 
x-2y=1
x+4y=7 

• 1
• -1
• 3
• 4

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

 Solve using elimination.
 7x + 2y = 24
  8x + 2y = 30

• (6,-9)
• (-9,6)
• No solution
• Infinite number of solutions

Tags

CCSS.8.EE.C.8B

Solve using elimination. 
−4x − 4y = 0
  8x + 8y = 0 

• (−6, −4) 
• Infinite number of solutions  
• No solutions
• (6, 4) 

Tags

CCSS.8.EE.C.8B

What is the best method do you use?

y = 6x − 11

−2x − 3y = −7

• Graphing

• Substitution because a variable is defined

• Elimination because both equations are in standard form.

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the best method to use?

−4x − 2y = −12

4x + 8y = −24

• Graphing

• Substitution because a variable is defined

• Elimination because the equations are in standard form.

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6