What is the solution of the equation when solved over the complex numbers?

x^2+20=0

x = or x =

(hurry! ) which expression is equivalent to the following complex fraction?

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is

Mrs. sling bought a pound of green beans for $1.80. how much will mrs. tennison pay for 3 1/2 pounds of green beans?