[10x*(-3)]+x=x²
解:
-30x+x=x²
x²+29x=0
x(x+29)=0
x1=0
x2=-29
(10×x-3)+x=x^2
10x-3+x=x^2
x^2-9x+3=0
因为 (-9)^2-4×1×3=69
所以 x1=4.5+√17.25
x2=4.5-√17.25
(10×x-3)+x=x^2
x^2-11x+3=0
(x-11/2)^2+3-(11/2)^2=0
(x-11/2)^2=121/4-3
(x-11/2)^2=109/4
x-11/2=±√109/2
x=(11±√109)/2