a)(5x-10)/6 -(2-2x)/15 = 1/3 +(4-3x)/30 aducem la acelasi numitor
5(5x-10) -2(2-2x)= 10+ 4-3x
25x-50 -4+4x=14 -3x
29x -54 =14 -3x
29x+3x=14+54
32x= 68
x= 68/32= 17/8
b)1 intreg 2/7= 9/2
|3x-9/2|=0 ∧ |3x-7/3|+2/5=0
3x-9/2=0 ∧ |3x-7/3|= -2/5 afirmatia nu poate fi adevarata intrucat continutul modulului trebuie sa fie intotdeauna un numar pozitiv
cum |3x-7/3|≠ -2/5 inseamna ca ecuatia nu poate avea solutii
c)(4-5x)² +(3-4x)²=0
|4-5x|=0 ∧ |3-4x|=0
4-5x=0 ∧ 3-4x=0
-5x=-4 ∧ -4x=-3
5x=4 ∧ 4x=3
x=4/5 ∧ x= 3/4
