Resposta :
a) (7a+1) (7a-1)
49â^2 - 1
b) (2+9x)² = 4 + 36x + 81x^2
c)(6x-y)² = 36x^2 - 12xy + y^2
d)(3x +2 sobre3 a)² = ((3x + 2)/3)^2 = 9x^2 + 12x + 4
9
a) [tex](7\text{a}+1)\cdot(7\text{a}-1)[/tex]
[tex]=(7\text{a})^2-1^2=49\text{a}^2-1[/tex]
b) [tex](2+9\text{x})^2[/tex]
[tex]=4+36\text{x}+81\text{x}^2[/tex]
c) [tex](6\text{x}-\text{y})^2[/tex]
[tex]=36\text{x}^2-12\text{xy}+\text{y}^2[/tex]
d) [tex](3\text{x}+\frac{2}{3})^2[/tex]
[tex]=9\text{x}^2+4\text{x}+\dfrac{4}{9}[/tex]