Write -1/9 + 10x - 2x^3 + x^5 - x ^4 in standard form

Ill mark the brainliest if you me with the these three questions 7,8,9

Which of the following is an example of a rational number? a. π b. √ 9 c. √ 8 d. 3.8362319

Which statement is true about the extreme value of the given quadratic equation? a. the equation has a maximum value with a y-coordinate of -21. b. the equation has a maximum value with a y-coordinate of -27. c. the equation has a minimum value with a y-coordinate of -21. d. the equation has a minimum value with a y-coordinate of -27.