Question

plzzz help If a + b + c = 5 and ab + bc + ca = 10 , prove that a^3 + b^3 + c^3 - 3abc = -25

Answer 1

Answer:

a+b+c=5

squaring both sides

a^2+b^2+c^2+2(ab+bc+ca)=25

Step-by-step explanation:

a^2+b^2+c^2=25-20

a^2+b^2+c^2=5

a^3+b^3+c^3-3abc=(a+b+c).(a^2+b^2+c^2-(ab+bc+ca))

5.(-5)

-25