Which expression represents the number

Answer:
8 + i
Step-by-step explanation:
What you need to simplify this is the following "definitions" of i to different powers.
[tex]i^1=i[/tex]
[tex]i^2=-1[/tex]
[tex]i^3=i^2*i=-1*i=-i[/tex]
[tex]i^4=1[/tex]
Now we can sub these in for the various powers of i in our expression:
[tex]6(1)+6(-i)-2(-1)+\sqrt{-1*49}[/tex]
Simplifying a bit:
[tex]6-6i+2+\sqrt{i^2*49}[/tex]
Since we know that the square root of i-squared is i, and that the square root of 49 is 7, we can get rid of the radial sign as follows:
6 - 6i + 2 + 7i
And the final answer, in a + bi form, is
8 + i