4. a) |x+7| = 3 b) -2|4-x| < -6
x+7=3 v x+7 = -3 -2(4-x) < -6 ∩ -2(4-x) > 6
x = -4 v x = -10 -8+2x < -6 ∩ -8+2x > 6
2x < 2 ∩ 2x > 14
x < 1 ∩ x > 7 x ∈ (-∞; 1) ∪ (7;∞)
5. a) x+4 ≠ 0
x ≠ -4
dziedzina = R-{-4}
b) zw = R
c) 0 = [tex]\frac{-2}{x+4}[/tex] + 1
- 1 = [tex]\frac{-2}{x+4}[/tex]
-1 ( x+4) = -2
-x-4=-2
-x=2
x= -2
d)
y = (-2/0+4 ) + 1
y = -1/2 + 1
y = 1/2
f0 = -2 x0 = 1/2
6. v1 = 60 km/h
t1 = 5h 30 minut
s = ?
s = v·t
s = 60 km/h · 5,5 h = 330 km
v2=75 km/h
s = 330 km
t2 = ?
t = s/v
t2 = 330km : 75 km/h = 4,4 h
4,4 h = 4 h 4/10 h = 4 h 4/10 · 60 minut = 4h 24 minuty
