If (x, y) is a solution of the system of equations above and x > 0, what is the value of xy ?
1
2
3
9
Choice A is correct. Substituting for y in the second equation gives
. This equation can be solved as follows:
Apply the distributive property. | |
Subtract 2x and 6 from both sides of the equation. | |
Combine like terms. | |
Factor both terms on the left side of the equation by 2x. |
Thus, and
are the solutions to the system. Since
, only
needs to be considered. The value of y when
is
. Therefore, the value of xy is
.
Choices B, C, and D are incorrect and likely result from a computational or conceptual error when solving this system of equations.