Two rival dry cleaners both advertise their prices. let x equal the number of items dry cleaned. store a's prices are represented by the expression 15x - 2. store b's prices are represented by the expression 3(5x + 7). when do the two stores charge the same rate?

:

Givens

Store A's price is

Store B's price is

Where represents the number of items.

Now, observe that the coefficient of both expressions is 15, because

Remeber that the coefficient of the x-variable is always the constant rate of change. Also, the given expressions can be expressed as linear functions

Observe that both Stores have already the same rate, which is 15.

Therefore, they have the same rate at any number of items dry cleaned.

What they have different is their initial condition, -2 and 21 respectively, but the rate is the same.

answer: she must produce at least 9,000 windows in order to make a profit of $48,000

explanation:

48,000 - 12,000 = 36,000

36,000/4 = 9,000