There is, for sure, effect of gravity on fire. We know for a fact that fires on Earth are "pointy" while those in zero-gravity are "round". This is because fire is simply glowing gas. Gas is matter and matter has weight. For a body to have weight, gravity must influence it in some way. 

Here, f(x)=x² -6 logx-3=0

f(2)=4-6 log2-3=-0.806

f(3)=9-6 log3-3=3.1373

f(2).f(3)=-0.806*3.1373=-2.529422 which is negative.

Hence, the root lies between 2 and 3

c₀ =(2+3)/2=2.5

f(2.5)=6.25-6 log 2.5-3=0.8623

Now

n	a(-ve)	b(+ve)	cn	f(cn)
0	2	3	2.5	0.8623
1	2	2.5	2.25	-0.050595
2	2.25	2.5	2.375	0.38664
3	2.25	2.375	2.3125	0.1631658
4	2.25	2.3125	2.28125	0.05506
5	2.25	2.28125	2.265625	0.001925

From the table,

f(2.265625)=0.001928<10^-2

Therefore, the...

Yes, a physical quantity can have magnitude and direction but still be a scalar if it doesn't obey the vector addition. An example is Electric Current which has magnitude and a fixed direction, but it does not follow vector laws of addition.

Here, f: A—>B

f(x)= (x-1)/(x+2)  ;  x   -2 

A= {-1,0,1,2,3,4}

B= {-2,1,-1/2,0,1/2,1/4,2/5}

Range = {-2,-1/2,0,1/4,1/2,2/5}

As range is not equal to codomain so the given function is not bijective. 

We can make it bijective by omitting {1} from set B