What is the square root -1?

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

Janie has $3. she earns $1.20 for each chore she does and can do fractions of chores. she wants to earn enough money to buy a cd for $13.50. write an inequality to determine the number of chores, c, janie could do to have enough money to buy the cd.

Need 50 will mark brainliest answer. find the lengths of all the sides and the measures of the angles.