2i^4-5i^3+3i^2+√-81 rewritten in a+bi form?

-1 + 14i.

Step-by-step explanation:

i^2 = - 1.

i^4 = i^2 * i^2

= - 1 * - 1 = 1.

i^3 = i^2 * i = - i.

√-81 = i√81 = 9i.

So

2i^4-5i^3+3i^2+√-81

= 2 - (5 * - i) - 3 + 9i

= - 1 + 5i + 9i

= - 1 + 14i.