Which of the following is an even function

f(x) = 7 is a even function

Solution:

Given that we have to find the even function

A function is even if and only if f(–x) = f(x)

Steps to follow:

Replace x with -x and compare the result to f(x). If f(-x) = f(x), the function is even.

If f(-x) = - f(x), the function is odd.

If f(-x) ≠ f(x) and f(-x) ≠ -f(x), the function is neither even nor odd.

Substitute x = -x in above function

Thus

So this is not a even function

f(x) = 8x

Substitute x = -x in above function

f(-x) = 8(-x) = -8x

Thus

So this is not a even function

Substitute x = -x in above function

Thus

So this is not a even function

f(x) = 7

f(-x) = 7

Thus f(-x) = f(x)

Thus it is a even function

distance covered by pamela in 9 l of fuel = 99km

let us apply unitary method here.

distance covered by pamela in 1 l of fuel =99/9 =11 km

now let us find distance covered by pamela if she has 12 l of fuel.

distance covered in 12 l = distance covered in 1 l of fuel * 12

we know that distance covered by here in 1 l is 11 km.

so distance covered in 12 l of fuel = 11*12 = 132 km.