A common trick for this sort of thing is to bring in a*b, which can act as a bridge between a*a and b*b. For example, try adding that to each side of...
Were you taught to write your calculations as multiplications of things (rather than of numbers) as you are doing? I don't think it's a safe thing to...
The word "string" refers to an ordered list (without reference to repetitions). It isn't used as often in math as, say, "permutation", so you can be...
Try first drawing a more accurate diagram (make it an actual angle bisector to get the relationships approximately right). Then construct an altitude...
It sounds like you haven't learned anything very advanced, so for the first question they probably expect you to state either the mean or the median....
I was a software engineer for many years, and have been teaching at a community college since 2004. Since 1998, I was a part of Ask Doctor Math (http://mathforum.org/dr.math/ and now http://themathdoctors.org/).