2: =>(x+2)^2-2x+3=x^2+10
=>x^2+4x+4-2x+3=x^2+10
=>2x+7=10
=>x=3/2(loại)
3: =>\(\dfrac{5x-2+\left(2x-1\right)\left(1-x\right)}{2\left(1-x\right)}=\dfrac{2-2x-2\left(x^2+x-3\right)}{2\left(1-x\right)}\)
=>2-2x-2x^2-2x+6=5x-2+2x-2x^2-1+x
=>-4x+8=8x-3
=>-12x=-11
=>x=11/12(nhận)