Algebra: Substitution

the product of 34 and z 

• 34/z

• z/34

• z X 34

• 34 - z 

take 10 away from s 

• 10 - s 

• s + 10

• s - 10

• s/10

six times the number of girls
Let g = number of girls

• 6 + g

• 6g

• g - 6

Define substitute.

• the number multiplied by a variable

• to replace a variable with a value or an expression

• a number standing alone

• to find the value of an expression

If x = 2, in the equation y = 3x - 5, what is the value of y?

This piece of string is 30 cm long. If Sarah cuts off p cm from one end, what length is left?

• 30 - p

• 30 + p

• 30/p

• 30 - 2p

29 - q = 13

• q = 17

• q = 16

• q = 42

• q = 13

If a = 4 b = 6, what is 3a + 5b?

• 40

• 42

• 44

• 46

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

• 34

• 36

• 35

If a=3, and b= -1, then (ab)² =

• -3

• -9

• 3

• 9