Răspuns:
1.a)3x²+5x+4=0
∆=25-4×12=24-48=-24
x≠R
b)2x²+7x+5=0
∆=49-40=9>0
x1 =-5/2. x2=-1 x=R
c)9x²-5x-2=0
∆=25+4×18>0
x=R
2.a)2x²+9x+10=0
∆=81-4×29=81-96<0
b)x²-5x+4=0
∆=25-16=9
x1,2=(5±3)/2=>x1=4. x2=1
c)2x²+x√7-7=0
∆=7+56=63
x1=√7/2. x2=-√7
d)-3x²-x+2=0
∆=1+24=25
x1 =-1. x2=2/3
e)x²√10-7x+√10=0
∆=10-40=-30<0 x≠R
f)x²+1/6x-1/6=0
∆=1/36+⁶4/6=(1+24)/36=25/36
x1=-1/2. x2=1/3
