It can be helpful to look at the numbers and the letters separately. The HCF of 4 and 2 is 2. The HCF of \(\text{x}^{2}\) and \(\text{x}\) is \(\text{x}\). So the highest common factor of \(\text{4x} ...

To check your answer when factorising multiply out the brackets to find if the answer matches with the question. If it doesn't, then you'll know there's something wrong. The first thing to do is ...