Given that y varies directly as x and inversely as 2m-1 and that y =5 when x=7and m=4, calculate of variation k

Inverse variation can be represented as:
y
=
k
x

k
=
y
.
x

where
k
is the constant
x
=
7
and
y
=
10

so ,
k
=
7
×
10
=
70

Now, we have the value of
k
and
x
=
10
, substituting these in the variation to find
y

k
=
y
.
x

y
=
k
x

y
=
70
10
=
7

on observing the values
when
x
=
7
,
y
=
10
, and
when
x
=
10
,
y
=
3

as the value of
x
decreases
y
increases and vice verse as they vary inversely.

All except for b, because polynomial functions can be quadratic, cubic, witticisms and etc only non negative exponents of negative it is not a polynomial function