if (x,y) is a solution to the system of equations above, what is the value of x^2?
Select the Correct Answer:
-51
3
9
144
Correct Choice:
9
Choice C is correct. The second equation gives y in terms of x, so a student can use this to rewrite the first equation in terms of x. Substituting -4x for y in the equation x^2 + y^2 = 153 gives x^2 + (-4 x^2)=153. This can be simplified to x^2+16x^2=153 or 17x^2 =153.
Since the question asks for the value of x^2, not x, dividing both sides of 17x^2=153 by 17 gives the answer: x^2=153/17=9.
