Two rival dry cleaners both advertise their prices. Store A’s prices are modeled by the expression 20x - 7, where x is the number of items brought in. Store B’s prices are modeled by the expression 4(5x + 7), where x is the number of items brought in. When do the two stores charge the same rate?

Step-by-step explanation:

Store A price is 20x-7

store B price is 4(5x+7)

Where x represents the number of items.

Now, observe that the coefficient of both expressions is 20, because 4(5x+7)=20x+7

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

y=20x-7

y=20x+7

Observe that both Stores have already the same rate, which is  20.

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

What they have different is their initial condition, -7 and +7 respectively, but the rate is the same..

a=24; b=12

step-by-step explanation:

a/b=2: 1

a=2b

36/(1+2)=12

b=12

a=24

70.30

step-by-step explanation: