Question

calcule:

(x+9)²=
(x²-1)=
(x+9)(x+1)=

Answer 1

(x+9)² = x² + 9x + 9x + 81 = x² + 18x + 81
(x²-1) = x² - 1
(x+9)(x+1) = x² + x + 9x + 9