Answer:
a. a(b)c
b. a(a(b)c)c
d. a(a(a(a)c)c)c
Step-by-step explanation:
We are given the following in the question:

a. a(b)c
It is given b belongs to W.

b. a(a(b)c)c

c. a(abc)c
a(abc)c does not belong to W because we cannot find x in W such that a(abc)c belongs to W.
d. a(a(a(a)c)c)c

e. a(aacc)c
a(aacc)c does not belong to W because we cannot find x in W such that a(aacc)c belongs to W.
Answer: y = 8x
Step-by-step explanation:
If you would like to solve for the positive value of x, you can do this using the following steps:
6 * x^2 - 54 = 0 /6
x^2 - 9 = 0
(x - 3) * (x + 3) = 0
1. x = 3
2. x = - 3
The correct result would be x = 3.
I prefer to use compatible numbers because by using this method it is easier to make a sum mentally. This is true because compatible numbers are close in value to the actual numbers. For a better understanding, let's take an example:
Suppose you have two numbers, namely 640 and 40. These two numbers are compatible for division because:
64 ÷ 4 = 16
So, we have used mental arithmetic to solve a more complex problem.