Question

If a + b + c = 4 and ab + bc + ca = 6 find the value of a3+b3+c3-3abc

Answer 1

Answer:

           -8

Step-by-step explanation:

From

 (a+b+c)³ = a³ + b³ + c³ + 3(a+b+c)(ab+bc+ca) - 3abc

we get

 a³ + b³ + c³ - 3abc = (a+b+c)³ - 3(a+b+c)(ab+bc+ca)

                                = 4³ - 3×4×6

                                = 64 - 72

                                = -8