Question

Kris drives 30 miles to work. For the first x miles, he drives 40 miles per hour. Then he is stuck in traffic and averages only 3 miles per hour the rest of the way. This expression can be used to find the total time Kris spends commuting: 40(x) + 3(30 - x).

Simplify the expressions.

1. 3(30 – x)


2. 40(x) + 3(30 - x)

Answer 1

• I'm sorry if it's not quite right.

1) -3x + 90

=(3)(30+−x)

=(3)(30)+(3)(−x)

=90−3x

=−3x+90

2) 37x+90

=40x+(3)(30)+(3)(−x)

=40x+90+−3x

Combine Like Terms:

=40x+90+−3x

=(40x+−3x)+(90)

=37x+90