Question

resolva a equação (3-y)(3+y)=0

Answer 1

(3-y)(3+y)=0
3 x 3 + 3 x y + (-y) x 3 + (-y) x (y) = 0
9 + 3y -3y - y² = 0
-y² + 9 = 0
(-1) -y² = - 9 (-1)
y² = 9
y = $\sqrt{9}$
y = 3