Quadratic Functions

[HNO]

I know how to put things from standard form into vertex form, but am unable to go from vertex form and back to standard.

What is the function y= 2(x-4)^squared -2 in standard form?


This is what I have so far:

1. 2(x-4)(x-4) - 2
2. (2x-8) (2x-8)
3. 4x^2 -16x -16x +64 -2

4. 4x ^ squared - 32x + 62

But this is completely wrong
(= Please help (=

 

[mmm4444bot]

unable to go from vertex form … back to standard

What is the function y= 2(x - 4)^2 - 2 in standard form?


This is what I have so far:

2(x-4)(x-4) - 2

(2x-8) (2x-8)

Note the exponent 2 in red above. The ^ symbol means exponentiation, so follow it by typing the actual exponent.


You do know how to convert; you're just making silly mistakes. :cool:

You inserted an extra factor of 2, and you somehow lost the minus 2.

You need to review the Order of Operations. We do multiplication from left to right in the order we see it.

2*(x - 4)*(x - 4)

First, we multiply 2(x - 4) using the Distributive Property. That multiplication yields 2x-8 giving us:

(2x - 8)(x - 4)

Second, use FOIL to multiply these two binomials together.

Now continue … and do not forget about the subtraction of 2 (i.e., the y-coordinate of the vertex shown in the given vertex form).

 

[HallsofIvy]

I know how to put things from standard form into vertex form, but am unable to go from vertex form and back to standard.

What is the function y= 2(x-4)^squared -2 in standard form?


This is what I have so far:

1. 2(x-4)(x-4) - 2
2. (2x-8) (2x-8)

This is wrong. You can multiply the first "2" into either of the "(x-4)" term but NOT both.
(2x- 8)(x- 4)- 2 or (x- 4)(2x- 8)- 2. What do you get when you multiply them out?

3. 4x^2 -16x -16x +64 -2

4. 4x ^ squared - 32x + 62

But this is completely wrong
(= Please help (=