Question

K
=
√
2
a
b
c
1
+
a
2
−
b
2
+
c
2
−
5
b


If
a
=
4
,
b
=
−
2
and
c
=
−
1

evaluate
K

Answer 1

This is an example of why some questions go unanswered.
The horrible text formatting just makes the eyes bleed.
Many times, copy/paste from formatted screen shots does not translate well.
Unfortunately, this is not clearly explained when students post their questions and attempt to include text from Word documents or other such data.
So, after you have posted, take a look at your submission to make sure it looks the way you want it to.