It's a y=mx+b equation, Carries' would be y=1/2 x - 125 (total profit is equal to the cupcake amount, each sold for 50 cents - the startup cost of 125). Juanita's would be y=2.25x-125. Comparing Carries' to Juanita's sales would mean that you would multiply x by 3 (no less than 3 times the ..). I may elaborate further on comparing in the comment section
according to the picture we have:
x.y=4.7
(7)x(7)y=49xy=(49)(4.7)=230.3
Since we are solving for n you have to isolate the n. Therefore, you want all the variables with an n in it on one side and all the variables without an n on the other side:) :
4k+3= -mn+n (There were a change in signs because for example you moved the -3 to the other side, therefore it can only be a negative on one side so now you have to change the sign to a positive:) hope you got that)
That would've been your answer because you cannot do anything else...Hope this helped :)
