The Total solution for NCERT class 6-12
a + b +c = 9Squaring, we get(a + b + c)2 = (9)2⇒ a2 + b2 + c2 + 2 (ab + be + ca)= 81⇒ 35 + 2(ab + bc + ca) = 812(ab + bc + ca) = 81 – 35 = 46∴ ab + bc + ca = 462 =23Now, a3 + b3 + c3 – 3abc= (a + b + c) [a2 + b2 + c2 –(ab + bc + ca)]= 9[35 – 23] = 9 x 12 = 108