a) (5x+1)/7≤(3-x)/4
4(5x+1)≤7(3-x)
20x+4≤21-7x
20x+7x≤21-4
27x≤17
x≤17/27
x≤0,(629)
x∈(-α, 0,(629)]
b)-3x/4+5≥4(1-x)
-3x/4=4-4x-5
-3x/4≥-4x-1
-3x≥4(-4x-1)
-3x≥-16x-4
-3x+16x≥-4
13x≥-4
x≥-4/13
x∈[-4/13,+α)
al II ex.
a)5(x+3)/x²+6x+9=
x²+6x+9=0
Δ=36-36=0
x1=x2=-6/2=-3
5(x+3)/x²+6x+9=5(x+3)/(x-3)² nu se poate simplifica
b)3(a+15)²/(a²-225)=3(a+15)²/(a+15)(a-15)=se simplifica cu a+15 si este=
=3(a+15)/(a-15)
c)4(x²-25)/(x+3)]·[(x²-9)/(x+5)²]=
[4(x+5)(x-5)/(x+3)]·[(x-3)(x+3)/(x+5)²]= simplificam cu x+5=
=[4(x-5)/(x+3)]·[(x-3)(x+3)/(x+5)]= simplificam cu x+3=
=[4(x-5)/1]·[(x-3)/(x+5)]=
=4(x-5)(x-3)/(x+5)
