Select all of the following that are quadratic equations. x3 - 4x2 + 3 = 0 x - 9 = 0 3x2 + 12x = 0 x2 + 9x -7 = 0 x2 - x = 8x + 2 x - 2 = 3x + 9

Plz answer asap! i will reward brainliest and 12 points for these three questions!take notice: these three questions are completely different! 1) what is the percentage of sugar in the syrup made of 10 kg of water and 4 kg of suugar? 2) what was the original price if after 10% discount it became $450? 3) at first a price was decreased by 12%, then it was disounted again by an additional 5%. what is the percent of the total discount? , and remeber i will award brainliest and 12 points!