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Algebra: Substitution with Squares and Square Roots (2)

In this worksheet, students substitute numbers into expressions containing squares and square roots.

'Algebra: Substitution with Squares and Square Roots (2)' worksheet

Key stage:  KS 3

Curriculum topic:  Algebra

Curriculum subtopic:  Substitute Numerical Values for Formulae/Expressions

Difficulty level:  

down

Worksheet Overview

QUESTION 1 of 10

When we substitute a number for a letter, we simply replace the letter with the number.

However, we must remember that 4b means 4 × b and 4b2 means 4 × b × b.

 

Example

Work out the value of the following expression when a = 4 and b = 9

3a2 - 7 - 2√b

 

Answer

3a2 - 7 - 2b

= 3 × a × a - 7 - 2 × b

= 3 × 4 × 4 - 7 - 2 x √9

= 48 - 7 - 2 × 3

= 48 - 7 - 6

= 35

Work out the value of the following expression when a = 4 and b = 2

3a2  + b2

Work out the value of the following expression when a = 4 and b = 2

3√a  + b2

Work out the value of the following expression when a = 4 and b = 2

3√a  - 2b2

Work out the value of the following expression when a = 9 and b = 1

4√a  - 6b2

Work out the value of the following expression when a = 9 and b = 1

4√a  + 5b2

Work out the value of the following expression when a = 2 and b = 1

4a2  + 5√b

Work out the value of the following expression when a = 3 and b = 0

4a2  + 5√b

Work out the value of the following expression when a = -3 and b = 0

3a2  - 3√b

Work out the value of the following expression when a = 3 and b = 25

3a2  - 3√b

Work out the value of the following expression when a = -2 and b = 64

4a2  - 2√b

  • Question 1

Work out the value of the following expression when a = 4 and b = 2

3a2  + b2

CORRECT ANSWER
52
  • Question 2

Work out the value of the following expression when a = 4 and b = 2

3√a  + b2

CORRECT ANSWER
10
  • Question 3

Work out the value of the following expression when a = 4 and b = 2

3√a  - 2b2

CORRECT ANSWER
-2
  • Question 4

Work out the value of the following expression when a = 9 and b = 1

4√a  - 6b2

CORRECT ANSWER
6
  • Question 5

Work out the value of the following expression when a = 9 and b = 1

4√a  + 5b2

CORRECT ANSWER
17
  • Question 6

Work out the value of the following expression when a = 2 and b = 1

4a2  + 5√b

CORRECT ANSWER
21
  • Question 7

Work out the value of the following expression when a = 3 and b = 0

4a2  + 5√b

CORRECT ANSWER
36
  • Question 8

Work out the value of the following expression when a = -3 and b = 0

3a2  - 3√b

CORRECT ANSWER
27
  • Question 9

Work out the value of the following expression when a = 3 and b = 25

3a2  - 3√b

CORRECT ANSWER
12
  • Question 10

Work out the value of the following expression when a = -2 and b = 64

4a2  - 2√b

CORRECT ANSWER
0
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