Question

dada a funçao f(x)=x²-3X determine os valores de x para que F(X)=4.

Answer 1

f(x)=x²-3x
f(x)=4
x²-3x=4
x²-3x-4=0
∆=b²-4ac
∆=(-3)²-4.1.(-4)
∆=9+16
∆=25
x=-b±√∆/2a
x=-(-3)-5/2.1
x=3-5/2
x=-2/2
x=-1
x=-(-3)+5/2.1
x=3+5/2
x=8/2
x=4
S={(-1, 4)}