SOLUTION: I am trying to figure this out and I am struggling so someone please help me. Why is (x+y)² not equal to x²+y²? Just lead me in the right direction because maybe I am just not unde

(x+y)² means to write (x+y) twice like this

(x+y)(x+y)  and then use FOIL to multiply
            it out

x²+xy+xy+y² and combine the middle two
            terms which are like terms

x²+2xy+y²

If you only got x²+y² you would leave out
the 2xy that you got from combining the
middle two terms after FOILing.

A numerical example to show that

(x+y)² is not the same as x²+y² is this

(2+3)² is not the same as 2²+3² because
(2+3)² equals (5)² which equals 25.  But
2²+3² equals 4+9 which equals 13. 

Edwin