We will use the PEMDA method.
5 • [(14 + 3 • 30) + 120] + 103 – 10
first, add what's in the parenthesis
5 • [(17 • 30) + 120] + 103 - 10
now let's multiply what's in the parenthesis
5 • [(510) + 120] + 103 - 10
continue to simplify what is in the parenthesis
5 • [630] + 103 - 10
now let's multiply
3150 + 103 - 10
no division? let's subtract!
3150 + 93
last step (:
3243 seems to be the answer