You may have thought that the notation meant that you had to do some multiplication, but it does not. The notation should be interpreted as follows:
Then rearrange and combine like terms.
meant that you had to do some multiplication, but it does not. The notation should be interpreted as follows:%7D%7B%5Cleft(%7Bx%7D%5Cright)%7D%3D%7Bf%7B%7B%5Cleft(%7Bx%7D%5Cright)%7D%7D%7D%2B%7Bg%7B%7B%5Cleft(%7Bx%7D%5Cright)%7D%7D%7D%3D%7B%5Cleft(%7B9%7D%7B%7Bx%7D%7D%5E%7B%7B2%7D%7D%2B%7B5%7D%7Bx%7D%2B%7B4%7D%5Cright)%7D%2B%7B%5Cleft(-%7B8%7D%7B%7Bx%7D%7D%5E%7B%7B2%7D%7D-%7B3%7D%7Bx%7D-%7B4%7D%5Cright)%7D\usepackage{cmbright}\Huge\)