((X2-3x):2+3)((x2-3x):2-4)=3

(((x²-3x)÷2)+3)(((x²-3x)÷2)-4)=3
((x²-3x)÷2)(1+3)(1-4)=3
((x²-3x)÷2)×(-12)=3
(-6)×(x²-3x)=3
-6x²+18x-3=0|÷(-3)
2x²-6x+1=0
D=(-(-6))²-4×2×1=36-8=28
x1=(-(-6)-√28)/2×2=(6-5,292)/4=0,708/4=0,177
x2=(-(-6)+√28)/2×2=(6+5,292)/4=11,292/4=2,823