ATAR Notes: Forum

VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Mathematical Methods CAS => Topic started by: Rose34 on March 11, 2020, 10:20:03 pm

Title: Could someone please tell me where I went wrong?
Post by: Rose34 on March 11, 2020, 10:20:03 pm

How to complete the square?
y=2x^2 -4x+6

My working out:
y=2(x^2 -2x+3)
y=2(x^2-2x+1+3-1)
y=2(x-1)^2+2

But the answer in the book in:
y=2(x-1)^2+4

Thanks in advance!

Title: Re: Could someone please tell me where I went wrong?
Post by: lm21074 on March 11, 2020, 10:49:58 pm

Hi Rose!

I think that the second step should be written as:


As we have taken out a common factor, all the terms have to be multiplied by two. It's like taking out a common factor of an expression such as: All terms inside the brackets need to be multiplied by the term on the outside.


Great question btw!
Good luck for your upcoming methods SAC :)

Title: Re: Could someone please tell me where I went wrong?
Post by: Rose34 on March 11, 2020, 11:11:47 pm

Quote from: lm21074 on March 11, 2020, 10:49:58 pm

Hi Rose!

I think that the second step should be written as:


As we have taken out a common factor, all the terms have to be multiplied by two. It's like taking out a common factor of an expression such as: All terms inside the brackets need to be multiplied by the term on the outside.


Great question btw!
Good luck for your upcoming methods SAC :)

Thanks!