Question

x^2+y^2=14 x+y=7 What is x-y ?

Answer 1

(7-y)^2+y^2=14

Answer 2

y^2-14y+49+y^2=14

Answer 3

\[(x+y)^2 = 7^2 \iff x^2+y^2+2xy = 49 \iff 14+2xy = 49 \]
\[2xy = 35 \iff xy = 17.5\]

\[(x-y)^2 = x^2+y^2-2xy =14-2(17.5) = -21\]
trying to be snazzy and something doesnt look right lolol

Answer 4

2y^2-28y+49=0

Answer 5

joemath i need ur help

Answer 6

http://openstudy.com/groups/mathematics/updates/4e4c88e20b8b95880499da50#/groups/mathematics/updates/4e4c8b610b8b9588049a0226

Answer 7

canu try helping her

Answer 8

agree

Answer 9

hmmm

Answer 10

i was following along until you had a perfect square=-21

Answer 11

thts easy hold up

Answer 12

lets imagine it is true that
\[x-y=\sqrt{21}i\] and if this makes sense.

Answer 13

now i am wondering whether there was a typo and it should be
\[x^2-y^2=14, x+y=7\] then you get the answer in a nanosecond