One solution to a quadratic equation is x equals start fraction negative nine plus 21 i over three end fraction full stop what is the solution in simplified standard form, x = a + bi, if a and b are real numbers?

The value, v, of kalani’s stock investments over a time period, x, can be determined using the equation v=750(0.80)^-x. what is the rate of increase or decrease associated with this account? 20% decrease 20% increase 25% decrease 25% increase