3i*7i

<-- Enter i raised to a power such as i^4 or a coefficient and i raised to a power such as 6i^7 or a product such as 3i^4 * 8i^6

Simplify the imaginary number product 3i*7i

Group coefficients and add powers of i
(3 * 7)i(1 + 1) = 21i2

We need to evaluate and simplify 21i2 where i = √-1

i2 = √-1 * √-1
i2 = (√-1)2
i2 = -1

Multiply our result by our coefficient of 21
21(-1) = -21