Suppose the line is y=mx+b
when x=3, y=15, so 15=3m+b
when x=-1, y=-13, so -13=-m+b
solve the system of these two equation, you get m=7, b=-6
so the linear equation is y=7x-6
This represents the function : y = log₆ (x).
Proof:
Rewrite this logarithmic function into an exponential form:
y = log₆ (x) ↔ x = 6^y
On the graph we see 2 major points A(1,0) and B(6,1). Plug them in x=6^y
1 = 6⁰ = 1 (true)
6 = 6¹ True, then this confirm that the graph equation is y = log₆ (x)
A = P(1 + r)^n
where A is the amount after n years, P = principal( initial amount), r = annual rate as a decimal fraction and n = number of years
If interest is accumulated say monthly then it would be
A = P(1 + r/12)^12n
For quarterly replace the 12 by 4
