My key can’t perform this but I can solve it on a sheet...
So here I really hopes this helps
<em>Greetings from Brasil...</em>
isolating a:
(a + b + c)/3 = z
(a + b + c) = 3z
<h2>a = 3z - b - c</h2>
The answer is C your welcome Gn
the difference from 40000 to the future value in 2020, namely 5 years later is simply the yield or interest amount.

To write

as a terminating decimal we will turn this fraction to a decimal. To do this we will divide the numerator by the deliminator and the result will be the decimal.Then we will check if it is a terminating decimal or repeating decimal. Lets do it:-

78 ÷ 25 = 3.12
3.12 is a terminating decimal. So,

as a terminating decimal is
3.12.Hope I helped ya!!