N-10+9n-3
n+9n=10n
10-3=7
so the answer is....
-13+10n
Solution
Step 1
The opposite angles of a parallelogram are equal:
Step 2

The equation is made true by the opposite angles theorem is
85 + y = 3y - 15
or
y = 50
Year 1: 500 + 0.25*500 = 500 [1 + 0.25]
Year 2: 500*[ 1 + 0.25] * [1 + 0.25] = 500 [1 + 0.25]^2
Year x: 500 [1 + 0.25]^x
Option d: A(x) = 500[1 + .25]^x, where .25 is the interest rate