Question

resolva as equações a seguir...
*Ajudaa Pfvr*

Answer 1

a)3x^2+15x=0
3x(x+5)=0

3x=0 x+5=0
x=0/3 x=-5
x=0

S={0, -5}

c)9.(2n-5).(n+2)=0
9.2n^2+4n-5n-10=0
18n^2-n-10=0

a=18 ▲=b^2-4ac
b=-1 ▲=(-1)^2-4.18.(-10)
c=-10 ▲=1+720
▲=721

n=-b+- √▲ :2a
n=-(-1)+-√721 :2.18
n=1+- √721 :36