A person invested $240 in an account growing at a rate allowing the money to double
every 14 years. How long, to the nearest tenth of a year would it take for the value of
the account to reach $430?

The number with which each term is multiplied is 100.
if we multiply each number with 100, it will eliminate decimals.
100 x (-m + 0.02 + 2.1m) = 100 x (-1.45 - 4.81m)
-100m + 2 + 210 = -145 -481m
Now you see that there is no decimal number in the expression.