Question

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Answer 1

i belive it is x = 4

Answer 2

5x^2+27x+28=0

5(28) is the same as 20(7)
and 20+7 is 27
replace 27x with 20x+7x in your equation
and then factor by grouping

Answer 3

I don't know how to do that... Never heard of it.

Answer 4

http://www.purplemath.com/modules/factquad3.htm
is this what you are doing?

Answer 5

judging by those boxes you can still use a table and what I said