Substitution

If a = 4 and b = 6, what is the value of 3a + 5b?

• 40
• 42
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• 46

If a=6 and b= 7,find the value of 15-a-b

• 2
• 3
• 4
• 1

If a=4,b=5 and c=6,find 2c-a-b

• 4
• 3
• 6
• 8

When x = 3, y = 6 and z = 7, find 2x - z

• -1
• -2
• -3
• -4

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

• 34
• 36
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• 37

If y = 4, find the value of 3y+5.

• 27
• 12
• 17
• 18

If y = 7, find the value of 2(y+4).

• 11
• 22
• 20
• 12

Work out the value of the following expressions when a = 3, b = 4 and c = 5.
2a

• 5
• 6
• 8
• 10

Work out the value of the following expressions when a = 3, b = 4 and c = 5.
3ab

• 10
• 12
• 15
• 36

Work out the value of the following expressions when a = 3, b = 4 and c = 5.
2a² + c²   

• 22
• 34
• 68
• 43