(x^2-3x-10)^2+(x-25)^2=0

x²-3x-10=0
x1+x2=3 U x1*x2=-10⇒x1=-2 U x2=5
(x+2)²(x-5)²+(x-5)²(x+5)²=0
(x-5)²[(x+2)²-(x+5)²]=0
(x-5)²(x+2-x-5)(x+2+x+5)=0
-3(x-5)²(2x+7)=0
x-5=0
x=5
2x+7=0
x=-3,5