[(a+8)x3+15]+5=44+12
[(a+8)x3+15]+5=56
(a+8)x3+15 =56-5
(a+8)x3+15=51
(a+8)x3=51-15
(a+8)x3=36
a+8=36:3
a+8=12
a=12-8
a=4
