Jawabanmu

2014-09-07T09:09:01+07:00
(-23) x (-21) + 40 - 51 x 12
 = 483 + 40  - 612
 = 523 - 612
 = -89
2014-09-07T09:09:25+07:00
(-23) x (-21) + 40 - 51 x 12 :
=483+40(-51 x 12)
=523-612
= -89