Question

Помогите упростить:
(x-3)²+x(x+9)

Answer 1

(x-3)²+x(x+9)=x²-6x+9+x²+9x=2x²+3x+9

Answer 2

$(x-3)^{2} +x(x+9)= x^{2} -6x+9+ x^{2} +9x=2 x^{2} +3x+9 \\ 2 x^{2} +3x+9=0 \\ a=2;b=3;c=9 \\ D= b^{2} -4ac=9-4*2*9=9-72=-63 \\ D\ \textless \ 0$