(15u-21)*3+27=234
(15u-21)*3=234-27
(15u-21)*3=207
(15u-21)=207:3
(15u-21)=69
15u=69+21
15u=90
u=90:15
u=6
(36t+98):14=25
(36t+98)=25*14
(36t+98)=350
36t=350-98
36t=252
t=252:36
t=7
(12v+30v+42):6=21
42v+42=21*6
42v+42=126
42v=126-42
42v=84
v=84:42
v=2
(15u-21)*3+27=234
(15u-21)*3=234-27
(15u-21)*3=207
(15u-21)=207:3
(15u-21)=69
15u=69+21
15u=90
u=90:15
u=6
(36t+98):14=25
(36t+98)=25*14
(36t+98)=350
36t=350-98
36t=252
t=252:36
t=7
(12v+30v+42):6=21
42v+42=21*6
42v+42=126
42v=126-42
42v=84
v=84:42
v=2