Harold has 3 pounds of red apples and 4.2 pounds of green apples from blue star grocery, where both kind of apples are $1.75 a pound. how much did harold spend on apples?

You multiply  1.75 times 3 pounds then do the same with 1.75 times 4.2 and then add your two results and that should be your answer which is 12.60

Y = x2 - 18x

 We look for the inverse of the function.
 To do this, let's determine the value of x:
 y = x2 - 18x
 y = (x + (-18/2)) ^ 2 - ((-18) ^ 2/4) + 0
 y = (x - 9) ^ 2 - 81
 y + 81 = (x - 9) ^ 2
 +/- root (y + 81) = (x - 9)
 +/- root (y + 81) + 9 = x
 We return the change:
 f (x) ^ - 1 = +/- root (x + 81) + 9
 Therefore, the values sought are:
 b = 1
 c = 81
 d = 9
  
 f (x) ^ - 1 = +/- root (x + 81) + 9 
 b = 1
 c = 81
 d = 9