Exercitiul 3 :
2 x ≤ 6, x ≤ 3
- 5 x < 5, x > - 1
{ 0 ,1 , 2 , 3 }
Exercitiul 5 :
a) 5x²+0,2x=0⇔x(5x+0,2)=0 x1=0 ⇔5x+0,2=0⇔5x=-0,2⇔x=-0,2/5 ⇔ x2=1/-25
b) 5x²-6x+1=0⇔Δ=b²-4ac=(-6)²-4*5*1=36-20=16
x1=-b-√Δ/2a=6-4/10=2/10=1/5 x1=1/5
x2=-b+√Δ/2a=6+4/10=10/10=1 x2=1
c) 3x(3x-2)+7+6⇔3x(3x-2)+13⇔9x²-6x+13
Exercitiul 6 :
26 + 60 = 86
140 - 86 = 54
54 : 3 = 18 l ( In primul poloboc )
18 + 60 = 78 l ( In al doilea poloboc )
62 + 78 = 140 l
( Exercitiul 4 in poza )