X^2-81/x^3+18x^2+81x при x=-8
X^
x2-81:x3+18x2+81x при х=-8
(x²-9²)/x³+18x²+81x)= (x-9)(x+9)÷x(x²+18x+81)= (x-9)(x+9)÷x(x+9)²=(x-9)÷x(x+9)= (-8-9)÷-8×(-8+9)= -17÷-8= 2.125