Completing the square

Question

$2x^2 - 6x - 5$

My workings are

$2 ( x^2 - 3x + (3/2)^2 - (3/2)^2 - 2.5 ) = 0$

$ 2 ( x - 1.5)^2 - 4.75 = 0$

$ (x-1.5)^2 = 2.375 $

From here I go on to find X which is not the correct answer .. Can anyone help me on where I have gone wrong ? Thanks in advance !

The $-4.75$ should be $-9.5$. There's a factor of 2 that you forgot to distribute onto the $-4.75$. — grand_chat, May 02 '16 at 04:41

score 0 · Answer 1 · answered May 02 '16 at 04:42

0

You divide by 2 twice. $ 2( (x-3/2)^2-4.75)=0 \rightarrow (x-3/2)^2=4.75$

answered May 02 '16 at 04:42

IrbidMath

1 Answers1