Question

B) (4x+2).(-2x+4)=

C) ( -x-10).(2x- 4)=

D) (1,2x+ 5). (2- 4,3x )=

Answer 1

A sua NOVA:

e)

(x+2x²+3). (- 2x+4 - x²)

x.(-2x) + x.4 + x.(-x²) + 2x².(-2x) + 2x².4 + 2x².(-x²) + 3.(-2x) + 3.4 + 3.(-x²)

= - 2x² + 4x - x³ - 4x³ + 8x² - 2x⁴ - 6x + 12 - 3x²
= - 2x² + 8x² - 3x² - x³ - 4x³ + 4x - 6x - 2x⁴ + 12
=          3x²              - 5x³       -  2x   - 2x⁴ + 12

= - 2x⁴ - 5x³ + 3x² - 2x + 12

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b)
(4x + 2). (- 2x + 4) 
= 4x.(-2x) + 4.4x + 2.(-2x) + 2.4
= - 8x² + 16x - 4x + 8 

= - 8x² + 12x + 8

c)
(- x - 10). (2x  - 4)
= - x.(2x) - x.(- 4) - 10.2x - 10.(- 4)
= - 2x² + 4x - 20x + 40

= - 2x² - 16x + 40

d)
= (1,2x + 5). (2 - 4,3x)
= 2.1,2x + 1,2x . (- 4,3x) + 5.2 + 5.(-4,3x)
= 2,4x - 5,16x² + 10 - 21,5x

= - 5,16x² - 19,1x + 10