Pls help asap tysm <3

Given the expression (7 ? 4i) ? (2 + 6i), perform the indicated operation and write the answer in the form a + bi.

Which equation can be solved to find one of the missing side lengths in the triangle? cos(60o) = cos(60o) = cos(60o) = cos(60o) = mark this and return

Look at the example below which shows how the product property of radicals is used to simplify a radical. use the product property of radicals to simplify the following radical.