Step-by-step explanation:

here,

a=2

b=1

To prove (a+b)²=a²+2ab+b²

taking L.H.S,

(a+b)² = (2+1)²

= 3² = 9

taking RHS,

a²+2ab+b² = 2²+2*2*1+1²

= 4+4+1 = 9

hence LHS=RHS,

therefore, (a+b)²=a²+2ab+b² proved