An=a1+d(n-1)
an=nth term
a1=first term, when n=1
d=common differnce=amount each term increases by
n=which one
so
when n=1, an=40
so a1=40
it seems to increas by 7 each time
an=40+7(n-1)
explicit formula is expanded
an=40+7n-7
an=33+7n is the formula
the domain is natural numbers because you can't have the -3rd term or the 0th term or the 3.24th term
domain is natural numbers
the formula is

or
Division and multiplication
Option A
The solution is 
<em><u>Solution:</u></em>
<em><u>Given system of equations are:</u></em>
3x + 6y = 1 ------ eqn 1
x - 4y = 1 ------ eqn 2
We have to find solution to system of equations
We can use substitution method
From eqn 2,
x = 1 + 4y -------- eqn 3
Substitute eqn 3 in eqn 1
3(1 + 4y) + 6y = 1
3 + 12y + 6y = 1
18y = 1 - 3
18y = -2
Divide both sides by 18

Substitute the above value of y in eqn 3

Thus solution is 
Measures of sum of the two opposite angles.
The answer is 2 radical 3