Which expression represents the second partial sum for ? 2(0.4) + 2(0.4)2 2(0.4)2 + 2(0.4)3 2 + 2(0.4) 0 + 2(0.4)1 timed

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