Question

if a + b + c = 4 and a b + BC + AC = 6 find the value of a cube plus b cube plus c cube minus 3 ABC

Answer 1

Given that,
a+b+c=4.................................................1
and,
ab+bc+ac=6..........................................2
Squaring on both sides to eq1 we have,
(a+b+c)^2=4^2

a^2+b^2+c^2+2(ab+bc+ac)=8

a^2+b^2+c^2+2×6=100 (by eq2)

a^2+b^2+c^2= -4 ....................................3
We know that,
a^3+b^3+c^3-3abc=(a+b+c)(a^2+b^2+c^2-ab-bc-ac)
By eq1 eq2 and eq3 we have,
a^3+b^3+c^3-3abc=(4)(-4-8)=4(-12) = -48

Hence a^3+b^3+c^3-3abc= -48

this is your answer....⛰☺⛰

Answer 2

Answer:

-96

Step-by-step explanation:

a2 plus b2 plus c2 equal 4

then u can solve it