Question

desenvolva as expressões:
A: (a+8)²=
B: (x+y)² =
C: (2-3a)²=
D: (x+5)(x-5)

Answer 1

$a) \\ (a + 8)^2\\ \\ (a + 8)*(a + 8) \\ \\ a^2 + 8a +8a + 64 \\ \\=> a^2 + 16a + 64 = 0$

$b) \\ (x + y)^2 \\ \\ (x + y)*(x + y) \\ \\ x^2 + xy + xy + y^2 \\ \\ => x^2 + 2xy + y^2 = 0$

$c) \\ (2 - 3a)^2 \\ \\ (2 - 3a) * (2 - 3a) \\ \\ 4 - 6a - 6a + 9a^2 = 0 \\ \\ 4 -12a + 9a^2 \\ \\ => 9a^2 - 12a + 4 = 0$

$d) \\ (x + 5) * (x - 5 ) \\ \\ x^2 - 5x + 5x - 25 = 0 \\ \\ => x^2 - 25 = 0$

Answer 2

a) $(a+8)^2=a^2+2a\cdot8+8^2=a^2+16a+64$

b) $(x+y)^2=x^2+2xy+y^2$

c) $(2-3a)^2=2^2-2\cdot2\cdot(3a)+(3a)^2=4-12a+9a^2$

d) $(x+5)(x-5)=x^2-5^2=x^2-25$