It will be 11:20 am or pm didn't really say but hoped it helped :)
The given question is 8+13+18+...... which is in arithmetic progression . And for arithmetic series, we have to use the following formula for nth term .

Here a =8 , d=5
So we get

And the required expression for n=7 is

The answer is:
a: 1 = 2(x^2<span> + 2</span>x<span>)
b:</span>1 = 2x^2 + 4<span>x
d:</span>3 = 2(x + 1)^2
you can tell these are your answer when you solve it.
Hope this helps!