Question

The operation* is defined as:
x*y= (x^2 +y^2+2xy)/(x+y).
If x*8=3, then which of the following is a possible value of x?
-11, 8, 11, -5, or 3

Answer 1

first note that (x^2 +y^2+2xy) = (x+y)^2
then u get:
x*y= x+y [1]

given that when y=8, x*y=3

therefore: equation [1] becomes:
3=x+8 this implies that x=-5