A quadratic polynomial is given by q(x)=x2+ax+b. It is known that x=1 and x=−2 are its zeros.
(i) Form two separate equations in a and b using the given zeros.
(ii) Solve the simultaneous equations to obtain the values of a and b.
(iii) Write q(x) in its expanded standard form and verify that both given numbers are indeed its zeros.