1. Check whether the following are quadratic equations:

(i) (x+1)2=2(x–3)

(ii) x2–2x=(–2)(3–x)

(iii) (x–2)(x+1)=(x–1)(x+3)

(iv) (x–3)(2x+1)=x(x+5)

(v) (2x–1)(x–3)=(x+5)(x–1)     

(vi) x2+3x+1=(x–2)2

(vii) (x+2)3=2x(x2–1) 

(viii) x3–4x2–x+1=(x–2)3