Question

Calcule os seguintes produtos:

a)-2x(x+4)
b)2x(3x+4y-2)
c)(x+5)(x²+2x-10)
d)(x+1)²
e)(x+7)(x+3)
f)(x-8)²
g)(3x+4)²
h)(2x-3)(2x+3)
i)(2x-4)²
j)(3x+3)²

Answer 1

a)
= - 2x.(x+ 4)
= - 2x² - 8x

¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨
b)
= 2x.(3x + 4y - 2)
= 2x.3x + 2x.4y - 2.2x
= 6x² + 8xy - 4x

¨*******************************************
c)
= (x + 5).(x² + 2x - 10)

= x.x² + x.2x + x.(-10) + 5x² + 5.2x + 5.(-10)

= x³ + 2x² - 10x + 5x² + 10x - 50 

= x³ + 7x² - 50

¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨
d)
= (x +1)²
= x² + 2x + 1

e)
= (x + 7).(x + 3)
= x² + 3x + 7x + 21
= x² + 10x + 21

f)
= (x - 8)²
= x² - 2.8x + 8²
= x² - 16x + 64

g)
 = (3x + 4)²
= (3x)² + 2.4.3x + 4²
= 9x² + 24x + 16

h)
= (2x - 3).(2x + 3)
= 2x.2x + 3.2x - 3.2x - 3.3
= 4x² + 6x - 6x - 9
= 4x² - 9

i)
= (2x - 4)²
= (2x)² - 2.4.2x + 4²
= 4x² - 16x + 16

j)
= (3x + 3)²
= (3x)² + 2.3.3x + 3²
= 9x² + 18x + 9