Question

Which statement best describes the effect on the graph of y = (x – 9)2 if the equation is changed to y = (x + 9)2? The graph moves up 18 units. The graph moves down 18 units. The graph moves left 18 units. The graph moves right 18 units.

Answer 1

The graph moves left 18 units.

Explanation:

Answer 2

Third option: The graph moves left 18 units.

Explanation:

Some transformations for a function f(x) are shown below:

If
`f(x)+k`, the function is shifted up "k" units.

If
`f(x)-k`, the function is shifted down "k" units.

If
`f(x+k)`, the function is shifted left "k" units.

If
`f(x-k)`, the function is shifted right "k" units.

In this case, we can observe that graph of
`y = (x - 9)^2` is changed to
`y = (x + 9)^2`

Since:

`-9+18=9`

We can conclude that the function
`y = (x - 9)^2` is shifted left 18 units to get the function
`y = (x + 9)^2`.