[(4xX-72):4+20]-64=20:4=5
(4xX-72):4+20=5+64=69
(4xX-72):4=69-20=49
4xX-72=49x4=196
4xX=196+72=268
X=268:4
X=67
[250-5x(X-5):5]x3=100-40=60
250-5x(X-5):5=60:3=20
5x(X-5):5=250-20=230
(X-5):5=230:5=46
X-5=46x5=230
X=230+5
X=235
(X-162):5+159=643-454=189
(X-162):5=189-159=30
X-162=30x5=150
X=150+162
X=312
