The correct answer is:
The equation is 7(c-0.75) = 2.80, and the regular price of a cookie is c = $1.15.
Explanation:
c is the regular price of a cookie. We know that today they are $0.75 less than the normal price; this is given by the expression c-0.75.
We also know if we buy 7 of them, the total is $2.80. This means we multiply our expression, c-0.75, by 7 and set it equal to $2.80:
7(c-0.75) = 2.80
To solve, first use the distributive property:
7*c-7*0.75 = 2.80
7c-5.25 = 2.80
Add 5.25 to each side:
7c-5.25+5.25 = 2.80+5.25
7c = 8.05
Divide each side by 7:
7c/7 = 8.05/7
c = $1.15.
