# How could i solve this?

## the equation $f \left(x\right) = {x}^{2}$ can be written as ${x}^{3} + p {x}^{2} + q = 0$ show that p=-1 and q=-20

Are you sure you have included all details here? Normally if $f \left(x\right) = {x}^{2}$, $f \left(x\right) \ne {x}^{3} + p {x}^{2} + q$, so there is something I don't understand here.