Plug In Number Substitution

What is the first step when evaluating (solving) the following expression? 2a + b if a = 3 and b = 4

• combine like terms

• substitute (plug) the number in for the variable

• add 2a with b

• look what answer my neighbor choose

What should the expression look like when the values (numbers) are substituted in for the variables (letters)?

• 3 + 3 + 2

• 3p + 5q + 2

• 5 + 5 + 2

• 3 + 5 + 2

Evaluate: p +q+2 if p=3 and q=5

• 12

• 10

• 8

If x=5, find the value of 7x-1

• 34

• 36

• 35

Which choice shows substitution correctly?

• 3x - (-6x +3) = 10

• 3(-6x + 3) - y = 10

Solve for x and y (Use Substitution)

y = 2x + 1

y = 4x - 1

• (1,3)

• (-1,-3)

• (-1,3)

• (3,1)

• (1,1)

If x = -3, in the equation -2x + y = 15, what is y? Type in the number.

Solve the system of equations using substitution:

-4x + 4y = 8

y = -2x - 10

• (-4, -2)

• (12, -34)

• (4, -18)

• (-2, -6)

• (-4, 6)

Solve the following systems of equations using substitution:

x = 6

y = 2x - 3

• (6, 6)

• (6, 9)

• (9, 6)

• (9, 9)

Solve using Substitution Method

y = -6

-3x - 6y = 24

• (6, 6)

• (6, -6)

• (4, -6)

• (-6, 4)