Answer:
0.027
Step-by-step explanation:

X^2 - 18x + 81 = 0
x^2 - 9x - 9x + 81 = 0
x(x - 9) - 9(x - 9) = 0
(x - 9)(x - 9) = 0
(x - 9)^2 = 0
x - 9 = 0
x = 9
Answer:
P = 10w
Step-by-step explanation:
Number of point per correct spelling = 10
Number of words spelt correctly = w
Total points, p
P = (number of points per correct spelling * number of words spelt correctly)
P = 10 * w
P = 10w