quadratic equation

[vscid]

If 6xy = x^2y + 9y, what is the value of xy?

(1) x = -2

(2) x < 0

[papgust]

https://www.beatthegmat.com/mgmat-ds-t15290.html

[Phirozz]

If 6xy = x^2y + 9y, what is the value of xy?

(1) x = -2

(2) x < 0

lets solve the equation first

6xy-y.x^2-9y = 0
y(6x-x^2-9) = 0
y = 0 or (x-3)^2 = 0
y = 0 or x = +3

st1) x = -2 ie x not equal to +3 so y definitely equal to 0, hence product xy = 0
st2) x < 0, it means x cannot be 3, so y definitely equals to 0, hence product
xy = 0

Hence it can be answered from both st1 and st2 independently

[STEVEN SPIELBERG]

IMOD.