MR-876 / 12a. problem

Simplify the following expression:

50x+30x+18x·5x-3x

50x+30x+18x·5x-3x

=50x·5x+50x·-3x+30x·5x+30x·-3x+18x·5x+18x·-3x

=250x-150x+150x-90x+90x-54x

=250x-54x