1) x^2+7x+12=(x+3.5)^2-0.25=(x+3.5-0.5)(x+3.5+0.5)=(x+3)(x+4)
2) x^2+3x-10=(x+1.5)^2-12.25=(x+1.5-3.5)(x+1.5+3.5)=(x-2)(x+5)
3) 4x^2-3x=0
x(4x-3)=0
x=0 или 4x-3=0=>x=3/4
4) a^2-64=(a+8)(a-8)=>a=8 и a=-8
5) 10x-2=5x
2=5x
x=2/5
6) 10(x+5)-8=6(x-4)+18
10x+50-8=6x-24+18
10x+42=6x-6
4x+48=0
x=-12