Question

Для достоверности

(x+6)^3-x(x+9)^2=27

Answer 1

$(x+6)^3-x(x+9)^2=27 \\ x^3+3x^2*6+3x*6^2+6^3-x(x^2+18x+81)=27 \\ x^3+18x^2+108x+216-x^3-18x^2-81x=27 \\ 27x=-189 \\ x=-7$