Question

( x-9)^2 = -x^2+ 15x+ 50

Answer 1

$( x-9)^2 = -x^2+ 15x+ 50\\\\x^2-18x+81+x^2-15x-50=0\\\\2x^2-33x+31=0\\\\D=(-33)^2-4\cdot2\cdot31=1089-248=841\\\\\sqrt D=\sqrt{841}=29\\\\x_1=\frac{33-29}{2\cdot2}=\frac{4}{4}=1\\\\x_2=\frac{33+29}{2\cdot2}=\frac{62}{4}=15,5$