(x-2)(x+1)(x+4)(x+7)=40
(x-2) (x+7)(x+1)(x+4)=40
(x²+5x-14)( x²+5x+4)=40
notam y= x²+5x
=> (y-14)(y+4)=40
y²-10y-56=40
y²-10y-96=0
Δ=100+384=484
y1=(10+22)/2=16 si y1=(10-22)/2= -6
x²+5x=16
x²+5x-16=0; Δ=25+64=89
x1=(-5+√89)/2
x2=(-5-√89)/2
x²+5x=-6
x²+5x+6=0
d=25-24
x3=(-5+1)/2= -2
x4=(-5-1)/2= -3
Solutii rationale: -2 si -3
