The science club is comparing options for purchasing new T-shirts. One company charges a $100 base fee plus an additional $3.50 per shirt. A second company charges a $120 base fee but only an additional $2.50 per shirt. The given expression represents the difference of the two companies’ average cost per shirt. Which expression is equivalent to the expression representing this situation?

A

Step-by-step explanation:

We have a common denominator, so we can just subtract the numerators, and leave it over the given denominator.

[(3.5x+100)-(2.5x+120)]/x

(3.5x+100-2.5x-120)/x

(1x-20)/x

(x-20)/x=A

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.