Question

помогите пжжжжжжжжжжжжжжжж( кроме ''d'')
Даю 5 баллов..........

Answer 1

3х²-7х+4=0
D=(-7)² - 4*3*4=49-48=1
х1=(7+1)/(2*3)=4/3 х2=(7-1)/(2*3)=1

5х²+6х+1=0
D=6² - 4*5*1=36-24=16
х1=(-6+4)/(5*2)=-1/5
х2=(-6-4)/(5*2)=-1

5х²+8х+3=0
D=8² - 4*5*3=64-60=4
х1=(-8+2)/2*5= -6/10 = -3/5
х2=(-8-2)/2*5= -10/10 = -1