Factor 75t 2 + 12 factor this problem out for me

12 is 33 1/3% of 36 what is the whole

What number must you add to complete the square x^2+12x=16

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?