Algebraic expressions – practice for Years 8–9
Sample questions on Algebraic expressions with the right answer and a worked solution, from easy to hard. In the Pickles Academy app a child gets new questions of the same kind every time, so they can't just learn the answers by heart.
- Subject
- Maths
- Year
- Years 8–9
- Curriculum area
- Number and algebra
Question types: Simplifying an expression
Rule: Algebraic expressions
(a + b)² = a² + 2ab + b², (a − b)² = a² − 2ab + b², (a + b)(a − b) = a² − b²
After expanding, collect like terms: x² with x², x with x, numbers with numbers.
Example: (x + 3)² − (x − 3)(x + 3) = x² + 6x + 9 − (x² − 9) = 6x + 18
Watch out: (x + 3)² is not x² + 9. And a minus in front of a bracket changes the signs of all the terms in it.
Sample questions
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Question 1 Easy
Simplify the expression: (x + 1)² − (x − 1)(x + 1)
Show the solution
Answer: 2x + 2How it works: (x + 1)² = x² + 2x + 1; (x − 1)(x + 1) = x² − 1; the difference is 2x + 2
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Question 2 Normal
Simplify the expression: (x + 2)² − (x − 1)(x + 1)
Show the solution
Answer: 4x + 5How it works: (x + 2)² = x² + 4x + 4; (x − 1)(x + 1) = x² − 1; the difference is 4x + 5
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Question 3 Hard
Simplify the expression: (x + 2)² − (x − 3)(x + 3)
Show the solution
Answer: 4x + 13How it works: (x + 2)² = x² + 4x + 4; (x − 3)(x + 3) = x² − 9; the difference is 4x + 13
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