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} ...

This is what goes outside the bracket: \(\text{5(? + ?)}\) To identify the terms that need to go inside the bracket, we must divide each term by the highest common factor.