Question

A potência (2x+5)² e calculada assim:
(2x+5)²=(2x+5)(2x+5)=
= 4x²+10x+10x+25=
= 4x²+20x+25
Agora, calcule

Answer 1

Podemos usar casos notáveis:
(a+b)²=a²+2ab+b²

a) (3x+1)² o nosso a=3x e b=1
= (3x)²+2×3x×1+1²
=9x²+6x+1

b)(2a-3b)²=4a²-12ab+9b²

c) (2a+b-5)²
=(2a+b)²-2×(2a+b)×5+5²
=4a²+4ab+b² -20a-10b+25

d)(2x+1)^3
=(2x+1)²(2x+1)
=(4x²+4x+1)(2x+1)
=8x^3+4x²+8x²+4x+2x+1
=8x^3+12x²+6x+1