Which quadratic has a graph with x-intercepts of 6 and -6?

a)
y = x2 - 6

b)
y = x2 - 36

c)
y = x2 + 36

d)
y = x2 -12x + 36

If x' & x" are the roots (or x intercepts) of a quadratic equation, then it could be written:
y= (x-x')(x-x")

Since -6 & +6 are the roots of the quadratic function, then it could be written

as follows y= (x+6)(x+6) ===> y= x²-36. So the answer is B