Evaluating Expressions

What is a variable? 

• A number such as x that represents an un specified number
• a number that varies or changes throughout a problem
• A number
• a letter

What is 4x if x=5?

• 20
• 16
• 9
• 45

What is 3x+(5+y) if x=2 and y=7?

• 18
• 28
• 8
• 3

What is 6+x when x=53?

• 59
• 50
• 47
• 90642

What is 34x-u+16y when x=2 u=14 and y=3?

• 102
• 43
• 2
• 107

Solve! (When x=8)

• 0
• No possible solution
• -4
• 8

What is  x-14(5+y) when x=13 and y=14

• -19
• 19
• Impossible 
• 16

What is  X+y+z+a-c      when x=11 y=3 z=4 a=14 and c=10? 

• 22
• 32
• 2
• 17

what is x•x when x=16

• 256
• 32
• 1
• 16

Evaluate -2x  if     x = 10

• -8
• 20
• -20