05/06/2026
QUESTION: Simplify fully (x² + 4)² − (x² − 2)²
SOLUTION: To simply fully, we must factorise the expression completely.
To factorise completely means that we factorise the expression till we come up with an expression that can't be further factotised.
Now let's go!
(x² + 4)² − (x² − 2)²
Note: The expression as a whole comes as a difference of two squares, such as a² – b².
Understand that
a² – b² = (a + b)(a – b)
We use this to factorise the given expression.
(x² + 4)² − (x² − 2)²
= [x² + 4 + (x² − 2)][x² + 4 − (x² − 2)]
Clear the internal brackets
= [x² + 4 + x² − 2][x² + 4 − x² + 2]
Combine like terms
=[2x² + 2][6]
= 6[2x² + 2]
The terms in the bracket has 2 common to each of them. So we factorise that.
= 6[2(x² + 1)]
Multiply 6 by the 2 to get 12
= 12(x² + 1)
This final expression can no longer be factotised. Therefore, we have simplified the given expression fully.
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