4. V50 =5V2 aprox este 7,2
V50-7-V50+91= -7+91= 84
5. -9 </ 5x-1 </ 9 /+1 => -8 </ 5x </ 10 /:5 => -8/5 </ x </ 2 => x ∈ [-8/5;2]
6. nu se vad prea clar puterile
7. a) A
b) F
c) F
8. 5+2V3=5+2*1,73=5+3,46=8,46
5+3V2=5+3*1,44=5+4,32=9,32 => 5+2V3 < 5+3V2
9. 3,5-4-V3-V3= -0,5-2V3
