Question

GENTE ME AJUDAA, NÃO CONSIGO FAZER ESSA 3 QUESTÕES..

Answer 1

x²-x-20=0
∆=(-1)²-4.1.(-20)
∆=1 + 80
∆=81
x=-(-1)±√81/2.1
x= 1±9/2
x1=1+9/2=10/2=5
x2=1-9/2=-8/2=-4
S={5,-4}


x²-7x+12=0
∆=(-7)²-4.1.12
∆= 49 - 48
∆=1
x= -(-7)±√1/2.1
x= +7±1/2
x1= 7+1/2=8/2=4
x2=7-1/2= 6/2=3
S={4,3}

3y²+2y-1=0
∆= 2²-4.3.(-1)
∆= 4 + 12
∆= 16
y= -2±√16/2.3
y= -2±4/6
y1= -2+4/6= 2/6=1/3
y2= -2-4/6= -6/6= -1
S={1/3, -1}