Solve for 10 - 6x - 9x^2 = -9x10−6x−9x 2 =−9x

x = (1 ±√41)/6

Step-by-step explanation:

10 -6x -9x² = -9x

9x² -3x -10 = 0 . . . . . subtract the left side

9(x² -1/3) -10 = 0 . . . factor first two terms

9(x² -1/3 +1/36) -10 -9/36 = 0 . . . . complete the square

9(x -1/6)² = 41/4 . . . . . add 41/4

x -1/6 = ±√(41/36) . . . . divide by 9, take the square root

x = 1/6(1 ± √41) . . . . . . .add 1/6

365

Step-by-step explanation:

2.15 rimes 20 is 325 so she is making 325 for 20 hours times .15 for her tips is 365