[(2x-1)(x+4)]*[(2x+3)(x+2)]+9=0
(2x²+7x-4)(2x²+7x+6)+9=0
2x²+7x-4=t
t*(t+10)+9=0
t²+10t+9=0
t1+t2=-10 U t1*t2=9
t1=-9 U t2=-1
2x²+7x-4=-9
2x²+7x+5=0
D=49-40=9
x1=(-7-3)/4=-2,5
x2=(-7+3)/4=-1
2x²+7x-4=-1
2x²+7x-3=0
D=49+24=73
x3=(-7-√73)/4
x4=(-7+√73)/4