Express the square root of -8 in i notation

What is the y-intercept of the graph of the equation y=3(2^x)

Abby is preparing fruit punch for her party. she starts with a bowl filled with liquid that has 1/2 fruit juice and 1/2 sprite, but she decides it's too fruity. so she pours out 1/4 of the liquid, and then fills the bowl up again with sprite. what fraction of the punch is now sprite?

Factor -8x3-2x2-12x-3 by grouping what is the resulting expression?