Question

factorise the following-
a2-7a+12

Answer 1

$$\begin{gathered} {\mathrm{a}}^2-7\mathrm{a}+12 \\ ={\mathrm{a}}^2-3\mathrm{a}-4\mathrm{a}+12 \\ =\mathrm{a}\left(\mathrm{a}-3\right)-4\left(\mathrm{a}-3\right) \\ =\left(\mathrm{a}-4\right)\left(\mathrm{a}-3\right) \end{gathered}$$