Tax code- Bible = 18528
tax code + Bible = 21472
add the two together to get
2* tax code = 18528 + 21472
tax code = 20000
The base case is the claim that

which reduces to

which is true.
Assume that the inequality holds for <em>n</em> = <em>k </em>; that

We want to show if this is true, then the equality also holds for <em>n</em> = <em>k</em> + 1 ; that

By the induction hypothesis,

Now compare this to the upper bound we seek:

because

in turn because

X is equal to 30 (vertically opposite angles)
y=180-50
=130 degrees (angles in a straight line equal to 180)
z=180-130-30 (angle sum of a triangle equal to 180)
z=20 degrees