Question

a+ b + c is equal to 9 and a b + BC + CA equal to 26 then the value of a cube plus b cube plus c cube-3 ABC​

Answer 1

Answer:

27

Step-by-step explanation:

a+b+c=9 and ab+bc+ca=26

squaring

(a+b+c)²=81

a²+b²+c²+2ab+2bc+2ca=81

a²+b²+c²-ab-bc-ca=81-3(ab+bc+ca)

                                81-3*26= 3                          

we know that

a³+b³+c³-3abc=(a+b+c)( a²+b²+c²-ab-bc-ca)

=(9) (3)=27