We want to think about how to change a function to move left and right, or up and down. First, think about what the root function looks like. g(x) = x2 is our root function, which should look like a parabola opening upward, with its vertex at (0,0). Now let's consider the function we have:
f(x) = x2 + 2
How is this different from the root function?
Has this function shifted from the root function?
How can you be sure?
Enter 0 for x, to find out the y-intercept. You should find this is now at (0, 2). How has this shifted from the base function?
So what we have done here is we have actually changed g(x) = x2 + 0 to f(x) = x2 + 2, which shifted the function vertically upward by 2.
What can you change now to increase it vertically by 6 additional units?
Now be careful! ACT and SAT both like to put trap answers, so we should expect an answer that looks like
x2 + 6
Can you tell me how many units this was shifted from f(x)?
Now that you have a handle on shifting functions vertically, how would you shift this 6 units to the right?
Remember, start with the base function, and try to shift that. If we EXPECT that the vertex is supposed to be at the point (6, 0), we can plug in x = 6 to our new function, and should find h(6) = 0. If you got h(6) = 12, then you added inside the parentheses.
Remember when shifting graphs, inside the parentheses, we shift with the opposite sign. When shifting vertically, it stays with the same sign.
If you've solved this correctly, now, you should have
h(x) = (x - 6)2
What if there are no answers that look like this?
You'll need to expand the binomial above!