Read the following SAT test question and then click on a button to select your answer.

y=x^2+9
y=6x

If (x,y) is a solution to the system of equations shown above, which of the following is the y-coordinate of the solution?

A.-18
B.-3
C.3
D.18

来源:可可英语 http://www.kekenet.com/sat/202001/603380.shtml