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I need help with this one please

I need help with this one please-example-1
User AVAVT
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Answer:

1. d) = g)

(3x - 2)(9x² + 6x + 4) = 27x³ - 8

2. e) = f)

(3x + 5) (3x - 4) = 9x² + 3x - 20

3. b) = h)

9x² - 24xy + 16y² = (3x - 4y)²

Explanation:

From the above question, we are to find the pairs through expansion or factorisation

a) (3x + 2)(9x² - 6x + 4)

b) 9x² - 24xy + 16y²

c) (4x - 3y)²

d) (3x - 2)(9x² + 6x + 4)

e) (3x + 5) (3x - 4)

f) 9x² + 3x - 20

g) 27x³ - 8

h) (3x - 4y)²

a) (3x + 2)(9x² - 6x + 4)

We expand.

3x(9x² - 6x + 4) + 2(9x² - 6x + 4)

27x³ - 18x² + 12x + 18x² - 12x + 8

27x³ - 18x² + 18x² + 12x - 12x + 8

= 27x³ + 8

c) (4x - 3y)²

We expand

(4x - 3y) (4x - 3y)

4x(4x - 3y) - 3y ( 4x - 3y)

16x² - 12xy - 12xy + 9y²

16x² - 24xy + 9y²

d) (3x - 2)(9x² + 6x + 4)

We expand

3x(9x² + 6x + 4) - 2(9x² + 6x + 4)

27x³ + 18x² + 12x - 18x² - 12x - 8

27x³ - 18x² + 18x² + 12x - 12x - 8

= 27x³- 8

e) (3x + 5) (3x - 4)

We expand

3x(3x- 4) +5(3x - 4)

9x² - 12x + 15x - 20

9x² +3x - 20

h) (3x - 4y)²

We expand

(3x - 4y) ( 3x - 4y)

3x(3x - 4y) -4y(3x - 4y)

9x² - 12xy - 12xy - 16y²

9x² - 24xy - 16y²

Hence:

1. d) = g)

(3x - 2)(9x² + 6x + 4) = 27x³ - 8

2. e) = f)

(3x + 5) (3x - 4) = 9x² + 3x - 20

3) b) = h)

9x² - 24xy + 16y² = (3x - 4y)²

User Qwurticus
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