a, $7x-2= 5x+3$
⇔ $2x=5$
⇔ $x= 2,5$
b, $2.(y-3)= 3.(y+1)$
⇔ $2y-6=3y+3$
⇔ $y=-9$
c, $1,2-3.(t-0,5)=2.(t-0,2)$
⇔ $1,2-3t+1,5= 2t-0,4$
⇔ $5t= 3,1$
⇔ $t= 0,62$
d, $\frac{2}{3}.(z-\frac{3}{4})= z-0,5$
⇔ $\frac{2}{3}.z-0,5= z-0,5$
⇔ $z= 0$
e, $3x-\frac{1}{3}= 2-\frac{x}{2}$
⇔ $3,5x= \frac{7}{3}$
⇔ $x= \frac{2}{3}$