Bryan needs a cheap courier service to deliver holiday gifts to his brother. The first courier service charges a flat fee of $18 plus $6 per pound. The second courier service charges a flat fee of $20 plus $5 per pound. If Bryan determines that the second courier service will be cheaper, how many pounds will Bryan ship?

x = 9

Step-by-step explanation:

Formula

The secant and tangent lines bear the following relationship

(tangent line )^2 = the outside secant line * length of the whole line

Givens

tangent line = 15

outside secant line = x

length of whole secant line = x + 16

Solution

15^2 = x ( x + 16)

15^2 = x^2 + 16x

225 = x^2 + 16x

x^2 + 16x - 225 = 0

Answer and Discussion

The equation has two factors.

(x - 9)(x + 25) =0

x + 25 has no meaning. There cannot be a negative length in this level of geometry.

The answer is x - 9 = 0

x = 9