Question

Hello people ~
factorise: : x^2 – 21x + 108​

Answer 1

`\\ \rm\rightarrowtail x^2-21x+108`

• Use midterm splitation

`\\ \rm\rightarrowtail x^2-12x-9x+108`

`\\ \rm\rightarrowtail x(x-12)-9(x-12)`

`\\ \rm\rightarrowtail (x-9)(x-12)`

Done!