Question

Find the values of a^2 + b^2 and a^4 + b^4 when a + b = 5 and Ab = 4.

Answer 1

You have now posted this question 5 times.
Both Damon and I have answered it, and you claim that you do not understand the method I used.
http://www.jiskha.com/display.cgi?id=1441676620

I used the standard method for this type of question.
based on the simple fact that
(a+b)^2 = a^2 + 2ab + b^2
or
(a+b)^2 = (a^2 + b^2) + 2ab
I then substituted your given values
5^2 = (a^2 + b^2) + 2(4)
giving me: a^2 + b^2 = 17

Damon's method, which you obviously did not even look at, actually finds the values of a and b

I am sorry to say, that if you do not understand such simple algebra, then you should not be studying math.