(5x^2-2x+10)^2 = (3x^2+10x-8)
<=> (5x^2-2x+10)^2 - (3x^2+10x-8)^2 = 0
<=> (5x^2-2x+10-3x^2-10x+8) * (5x^2-2x+10+3x^2+10x-8) = 0
<=> (2x^2-12x+18) * (8x^2+8x+2) = 0
<=> (x^2-6x+9) * ( 4x^2+4x+1) = 0
<=> (x-3)^2 * (4x+1)^2 = 0
<=> x-3=0 hoặc 4x+1=0
<=> x=3 hoặc x=-1/4
Vậy...