Question

para que valores de "x" a função y = -4x+1 torna-se positiva, negativa e nula

Answer 1

$\displaystyle-4x+1>0\\-4x>-1\\x<\frac{1}{4}\\\\\\-4x+1<0\\-4x<-1\\x>\frac{1}{4}\\\\\\-4x+1=0\\-4x=-1\\x=\frac{1}{4}$

Answer 2

positiva;

-4x+1 > 0. ==> *(-1)

4x -1 < 0

4x < 1

x < 1/4

negativa:

-4x+1 < 0 ==> *(-1)

4x -1 > 0

4x > 1

x > 1/4

nula:

-4x+1 = 0

1 = 4x

x = 1/4