Answer:
4x
Step-by-step explanation:
Given the expression
4x² - 36x
Get the individual factor of each terms
4x² = 4 * x * x
36x = 4 * 9 * x
4x² - 36x = 4x(x-9)
From both factors we can see that 4*x is common to them, hence the greatest common factor is 4x