How do you factor 4x squared minus 8x?

4x^(2) - 8x

'4' is common to both '4' & '8' . So tak outr '4'.

Hence

4(x^(2) - 2x)

Inside the brackets 'x' is common to both 'x^(2) & '2x'. So take out 'x'.

Hence

4x(x - 2)

Done , fully factored.