Someone please help. Describe the pattern that is being followed:
2, 4, 16, 256 . . .

What is the next number in the sequence?

Which of the following parabolas opens down?

Gabrielle's age is two times mikhail's age. the sum of their ages is 84. what is mikhail's age?

Aclassmate thinks that solving a system by graphing gives an exact answer when the lines appear to cross at a grid point, but only an approximate answer when they don't. explain why this isn't true.