+0

# Standard Form conversion

+5
202
3
+59

How would I convert this equation to standard form? y = -2 (x - 6)^2 + 8

#1
+91510
+10

$$\\y = -2 (x - 6)^2 + 8\\ y=-2(x^2-12x+36)+8\\ y=-2x^2+24x-72+8\\ y=-2x^2+24x-64\\$$

Melody  Dec 15, 2014
Sort:

#1
+91510
+10

$$\\y = -2 (x - 6)^2 + 8\\ y=-2(x^2-12x+36)+8\\ y=-2x^2+24x-72+8\\ y=-2x^2+24x-64\\$$

Melody  Dec 15, 2014
#2
+59
+5

I'm confused. How did you get the -12x?

#3
+91510
+5

Sorry I took so long to get back to you I have been busy today.

I am very glad that you asked - I like to get feed back :)

This is the long way I could have done     $$(x-6)^2$$

$$\\(x-6)^2\\ =(x-6)(x-6)\\ =x(x-6)\;\;-6(x+6)\\ =x^2-6x\;\;-6x-36\\ =x^2-12x+36$$

Now $$(x-6)^2$$     is a perfect square.   There is a short cut method.

$$\\(a\pm b)^2=a^2\;\pm\;(2*a*b)\;+\;b^2\\ so\\ (x-6)^2=x^2\;-\;(2*x*6)\;+\;6^2=x^2-12x+36$$

I sometimes use this method when I want to square numbers in my head

eg

$$\\23^2\\ =(20+3)^2\\ =20^2+(2*20*3)+3^2\\ =400+120+9\\ =529$$

Melody  Dec 16, 2014

### 17 Online Users

We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details