Question

como resolver -4x²+28x = 0

Answer 1

$-4x^2+28x=0 \\ \\ 4x^2-28x=0 \\ \\ fatorando \\ \\ x(4x-28)=0 \\ \\ 4x-28=0~~~~~~~e~~~~~~x=0 \\ 4x=28 \\ x=28\div4 \\ x=7 \\ \\ V=\{0,7\}$

Answer 2

x(-4x+28)=0
x=0 v -4x=-28
x=0 v x= 28/4
x=0 v x=7 
c.s(0;7)

Answer 3

x(-4x+28)=0
x=0 v -4x=-28
x=0 v x= 28/4
x=0 v x=7