Given: a−b=2,a3−b3=26 We know that a3−b3=(a−b)(a2+b2+ab) (a+b)2=(a2+b2+2ab) Putting values, 26=2(a2+b2+ab) 13=(a2+b2+ab).... (i) 13=(a2+b2+ab−2ab+2ab) 13=(a−b)2+3ab The value of (a−b)2=22=4 ⇔13=4+3ab 9=3ab ab=3.... (ii) to find (a+b)2=(a2+b2+2ab) (a+b)2=(a2+b2+ab+ab) Using (i) and (ii) we get, (a+b)2=13+3=16