112²-62²=(112-62)(112+62)=50*174=50*2*87=100*87=8700
X³(x - 2) + 2x²(x - 2) - 21x(x - 2) + 18(x - 2) = 0
(x - 2)*(x³ + 2x² - 21x + 18) = 0
(x - 2) *(x²(x - 1) + 3x(x - 1) - 18(x - 1)) = 0
(x - 2)*(x - 1)*(x² + 3x - 18) = 0
(x - 2)*(x - 1)*(x(x - 3) + 6(x - 3)) = 0
(x - 2)*(x - 1)*(x - 3)*(x + 6) = 0
x - 2 = 0
x = 2
x - 1 = 0
x = 1
x - 3 = 0
x = 3
<span>x + 6 = 0
x = - 6</span>
Sina/cosa:[cosa/sina*1/cos²a)-1=sina/cosa*sinacosa-1=sin²a-1=-cos²a
Такой вот не особо красивый ответ