Substituting for One Variable

3x + 8   if x = 2

• 13

• 14

• 15

• 16

Evaluate 4y  if       y = 3

• 7

• 12

Evaluate 2r + 1      if   r = 3

• 6

• 5

• 7

• 8

Evaluate 7y - 3y for y=2

• 40

• 73

• 8

• 4

Evaluate the expression.  Let a = 4, what is:
5a + 7a - 8

• 48

• 28

• 40

• 35

Evaluate -2x  if     x = 10

• -8

• 20

• -20

To replace a variable with a number is ___

Solve the following system by substitution:

7x + y = -20 and y = 3x + 10

Solve the following system by substitution:

y = 2x + 5 and -4x + y = 9

Solve the following system by substitution:

5x + y = -10 and y = -6x - 13