[tex]\begin{gathered} a)x^2\text{ - 11 = 4x} \\ \text{ x}^2\text{ - 4x = 11} \\ ory=x^2\text{ - 4x - 11} \\ b)15x-21=5x^2 \\ \text{ 5x}^2\text{ - 15x = -21} \\ \text{ f(x) = 5x}^2\text{ - 15x + 21} \\ c)-7x^2\text{ = 10 - 13x} \\ \text{ 7x}^2\text{ - 13x = -10} \\ f(x)=7x^2\text{ - 13x + 10} \\ \end{gathered}[/tex]
