If is the solution to the system of equations above, what is the value of
?
Choice B is correct. Subtracting the second equation, , from the first equation,
, results in
, or
. Combining like terms on the left-hand side of this equation yields
.
Choice A is incorrect and may result from miscalculating as
. Choice C is incorrect and may result from miscalculating
as 5. Choice D is incorrect and may result from adding 9 to 4 instead of subtracting 9 from 4.