Factorise by grouping method :
`x(6x - 5y) - 4(6x - 5y)^(2)`

Answer

To factorise the expression \( x(6x - 5y) - 4(6x - 5y)^2 \) by grouping, we can follow these steps:

### Step 1: Identify the common factor
The expression has a common factor of \( (6x - 5y) \). We can factor this out.

### Step 2: Rewrite the expression
We can rewrite the expression as:
\[ (6x - 5y) \left( x - 4(6x - 5y) \right) \]

### Step 3: Simplify the second part
Now, we simplify the second part of the expression:
\[ x - 4(6x - 5y) = x - 24x + 20y = -23x + 20y \]

### Step 4: Combine the factors
Now we can combine the factors:
\[ (6x - 5y)(-23x + 20y) \]

### Final Answer
Thus, the factorised form of the expression is:
\[ (6x - 5y)(20y - 23x) \]