Which statement best describes the effect on the graph of y = (x – 9)2 if the equation is changed to y = (x + 9)2?

Use the symbol "^" to denote exponentiation.   write y = (x-9)^2 and y = (x + 9)^2.like y=x^2, the graphs of the two given functions are vertical parabolas which open upward.the graph of y=x^2 has its vertex at (0,0).   that of y = (x-9)^2 has exactly the same shape, but has its vertex at (9,0).   that of y = (x+9) has the same shape, but has its vertex at (-9,0).   the principle here is "horizontal shift."