What two numbers add to 18 and multiply
to 0.

18 and 0

Step-by-step explanation:

Anything multiplied by 0 is 0, so 0 must be one of the numbers

Anything added to 0 is itself, so 18 added to 0 is 18

Hope that makes sense.

a complex number is a number that can be expressed in the form a + bi, where a and b are real numbers, and i is a solution of the equation x2 = −1. because no real number satisfies this equation, i is called an imaginary number. has no real solution, since the square of a real number cannot be negative.

no not all of them.

step-by-step explanation:

some of them have a square base.