What two numbers multiple to 110 but also adds up to -21

Simplify (1/2)4th power a. (1/16) b.(1/8) c.(1/4)

Solve this riddle: i am an odd number. i an less than 100. the some of my digit is 12. i am a multiple of 15. what number am i?

X+y=-4 x-y=2 use elimination with adding and subtraction