A pound of apple costs $2.50. Represent the cost of n pounds.

2.50n

Step-by-step explanation:

If im reading this right you're trying to represent the number of n pounds, so 2.50 * n

say you had 3 pounds:

2.50 (3) = 7.50

i used to know how to do this in 7th but i forget easily

step-by-step explanation:

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4