{[(a•11)-3•7]•2}-(99+100)=1
{[a•11-21]•2}-199=1
(a•11-21)•2=1+199
(a•11-21)•2=200
a•11-21=200:2
a•11-21=100
a•11=100+21
a•11=121
a=121:11
a=11
v:{[(11•11)-3•7]•2}-(99+100)=[(121-21)•2]-199
=(100•2)-199
=200-199
=1
Sper că te-am ajutat!