a)(3•a+5)•5-3= 292
15a+25-3=292
15a+22=292
15a=292-22
15a=270
a=270:15
a=18
b).(b-5)•2=30
2b-10=30
2b=30+10
2b=40
b=40:2
b=20
c) (c-17)•3+15=45
3c-51+15=45
3c-36=45
3c=45+36
3c=81
c=81:3
c=27
d) [2•(d-30)-45]=165
2d-60-45=165
2d-105=165
2d=165+105
2d=270
d= 270:2=135
Sper ca te-am ajutat.... Coroana :D