Which expression best completes the following definition of a complex number?

The set of all numbers in the form__where a and bare real numbers and i
equals √-1

A. bi+a
B. a/bi
C. a+bi
D. a(bi)

What percent of the circle below is shaded?

Two friends are reading books. jimmy reads a book with 21,356 words. his friend bob reads a book with one-and-a-half times as many words. which expression represents the number of words bob reads?

Simplify (4x^2 - 8xy + 2y^2) - (9x^2 - 4xy - 7y^2) a. -5x^2 + 4xy + 9y^2 b. -5x^2 - 4xy + 9y^2 c. -5x^2 + 12xy + 4y^2 d. -5x^2 - 4xy - 5y^2