Systems of Equations Substitution

^{What is the solution?} 

• 1
• -2
• (1, 2)
• (1, -1)

Solve the following systems of equations using substitution:

y = 8

y = -4x + 4

• (8, -1)

• (-28, 8)

• (-1, 8)

• (8, -28)

Solve the following systems of equations using substitution:

x = 6

y = 2x - 3

• (6, 6)

• (6, 9)

• (9, 6)

• (9, 9)

How many solutions does the graph have?

• One solution

• No solution

• Infinite solutions

Solve the following systems of equations using substitution:

y = 3 - x

3y + x = 5

• No solution

• (1, 2)

• (3, 0)

• (2, 1)

Solve:
y=8x+1
y=6x+3

• (1, 9)
• (4, 14)
• (0, 1)
• (2, 4)

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

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

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

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.

Solve the following systems of equations using substitution:

2y + x = -15

x = 3y

• (-3, -9)

• (-9, -3)

• (-3, 9)

• (9, -3)