Question 1126432
looks like you have the right answer.


when you replace a with -3, the expression becomes (4*(-3)^2 - (-3)^3) / (-3)^4.


this results in 36 + 27) / 81 which results in 63/81 which results in 7/9.


to simplify the algebraic expression, your would do the following:


start with (4a^2 - a^3) / a^4.


factor out an a^2 to get (a^2 * (4 - a)) / a^4.


since a^2 / a^4 equals a^(2-4) = a^(-1) which is equal to 1/a^2, the expression becomes (4 - a) / a^2.


i'm not quite sure, but i think that's as simple as it gets.


when a = -3, that becomes (4 - (-3)) / (-3)^2 which becomes 7/9.


the original expression and the final expression give you the same answer, so it appears that the simplification is correct.