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secondary 4 | E Maths
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I need someone to explain this to me step by step. I don't really understand what my math teacher taught.
Date Posted: 4 years ago
Views: 391
8x²(x² + 2)² - 2x(4x³ + 1)(x² + 2)
Notice the common factor (x² + 2) for both terms. So we factor that out first.
= 8x²(x² + 2)(x² + 2) - 2x(4x³ + 1)(x² + 2)
= (x² + 2) (8x²(x² + 2) - 2x(4x³ + 1))
Then, expand the terms inside, and simplify
= (x² + 2) (8x⁴ + 16x² - 8x⁴ - 2x)
= (x² + 2) (16x² - 2x)
Now, factorise 16x² - 2x. The common term is 2x so factor that out.
= (x² + 2) ( (8x)(2x) - (1)(2x) )
= (x² + 2)(2x)(8x - 1)
= 2x(8x - 1)(x² + 2)
Notice the common factor (x² + 2) for both terms. So we factor that out first.
= 8x²(x² + 2)(x² + 2) - 2x(4x³ + 1)(x² + 2)
= (x² + 2) (8x²(x² + 2) - 2x(4x³ + 1))
Then, expand the terms inside, and simplify
= (x² + 2) (8x⁴ + 16x² - 8x⁴ - 2x)
= (x² + 2) (16x² - 2x)
Now, factorise 16x² - 2x. The common term is 2x so factor that out.
= (x² + 2) ( (8x)(2x) - (1)(2x) )
= (x² + 2)(2x)(8x - 1)
= 2x(8x - 1)(x² + 2)
See 1 Answer
The question asks to factorise the expression so common terms should be taken out first. What you've done is to simplify and expand the expression instead.
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