Question

cum se rezolva: a) 2x la patrat-5x+2. b)(2xpatrat-x)(2xpatrat-2x+x-2)-8. PLSSSSS HELPPPPPP

Answer 1

a)2x^2-5x+2=0
a=2
b=-5
c=2
∆=25-16
∆=9
x1=5-3/4
x1=1/2
x2=2
ec se mai poate scrie
2(x-1/2)(x-2)=2(x^2-2x-x/2+1)=2x^2-5x+2
b)(2x^2-x)(2x^2-2x+x-2)-8=0
-2x+x=-x
(2x^2-x)(2x^2-x-2)-8=0
facem substituție
fie 2x^2-x=t
t(t-2)-8=0
t^2-2t-8=0
t^2+2t-4t-8=0
t(t+2)-4(t+2)=0
(t+2)(t-4)=0
t1=-2
t2=4
x^2-x=-2
x^2-x+2=0
x1,2 nu sunt reale ∆<0
x^2-x=4
x^2-x-4=0
∆=1+16
x3=1-√17/2
x4=1+√17/2