a) 4x-1=0
⇔x=1/4
x-2=0
⇔x = 2
BXD x | 1/4 2
f(x) | + 0 - 0 +
f(x) >0 ⇔ x ∈ (-∞; 1/4) ∪ (2;+∞)
f(x)<0 ⇔ x ∈ (1/4; 2)
b) 3x-2=0⇔x=2/3
5-3x=0 ⇔x=5/3
BXD
x | -∞ 2/3 5/3 +∞
f(x)| _ 0 + 0 -
f(x)>0 ⇔x ∈ (2/3;5/3)
f(x)<0 ⇔ x ∈ (-∞; 2/3) ∪ (5/3; +∞)
c) 4x-2 =0⇔x = 1/2
3x+1=0 ⇔ x= -1/3
BXD
x | -∞ -1/3 1/2 +∞
f(x) | + || - 0 +
f(x)>0⇔X ∈ (-∞ ; -1/3 )∪(1/2 ; +∞)
f(x)<0 ⇔x ∈ (-1/3; 1/2)