f xy = 3, what is the value of xy(x + y) ?
(1) x – y = 2
(2) x^2 + y^2 = 10
1) x - y = 2
xy = 3
x and y will have two values
Insuff
2. (x+y)2 -2xy = 10
x+y = +- 4
insuff.
hence IMO E
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E
Almost fell into the trap with 2
1) x-y = 2
solving this in combination with xy =3, you get a quadratic which can have 2 sets of soultions
Insuff
2) x^2 + y^2 = 10
(x+y)^2 = x^2 + y^2 + 2(xy)
= 10 + 6
= 16
hence (x + y) = +- 4
Insuff
Hence E)
Almost fell into the trap with 2
1) x-y = 2
solving this in combination with xy =3, you get a quadratic which can have 2 sets of soultions
Insuff
2) x^2 + y^2 = 10
(x+y)^2 = x^2 + y^2 + 2(xy)
= 10 + 6
= 16
hence (x + y) = +- 4
Insuff
Hence E)
