SOLUTION: if x + y = 12 and x - y = 1/3, then x^2 -y^2 =

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Question 1041607: if x + y = 12 and x - y = 1/3, then x^2 -y^2 =
Found 2 solutions by jim_thompson5910, ikleyn:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
x+y = 12
x-y = 1/3

Multiply out the two equations (left sides group together, right sides group together)

(x+y)*(x-y) = 12*(1/3)
(x+y)*(x-y) = 4
x^2 - y^2 = 4 ... difference of squares rule


The final answer is 4.

Answer by ikleyn(52790) About Me  (Show Source):
You can put this solution on YOUR website!
.
Do you know this identity

(x+y)*(x-y) = x%5E2+-+y%5E2.

It is valid for all real numbers x and y.

If you don't know it or if you are not sure, see the lesson The difference of squares formula in this site.