if X + Y + Z is equals to 9 and xy + Y Z plus ZX is equals to 23 then find the value of x cube + y cube + Z cube minus 3 x y z
Answers
Answered by
16
Answer:
HELLO THERE!!
x+y+z=9
(x+y+z)^2=81
x^2+y^2+z^2+2(xy+yz+zx)=81
x^2+y^2+z^2+2 (23)=81
=81-46
=35
x^3+y^3+z^3-3xyz=(x+y+z)(x^2+y^2+z^2-(xy+yz+zx)
=(9)(35-23)
=9 (12)
=108
HOPE IT HELPS!! PLEASE MARK AS BRAINLIEST!!
Answered by
23
Step-by-step explanation:
Given -
- x + y + z = 9
- xy + yz + zx = 23
→ -1(-xy - yz - zx) = 23
→ -xy - yz - zx = -23
To Find -
- Value of x³ + y³ + z³ - 3xyz
As we know that :-
(x + y + z)² = x² + y² + z² + 2xy + 2yz + 2zx
→ (9)² = x² + y² + z² + 2(xy + yz + zx)
→ 81 = x² + y² + z² + 2(23)
→ 81 - 46 = x² + y² + z²
→ x² + y² + z² = 35
Now,
As we know that :-
x³ + y³ + z³ - 3xyz = (x + y + z)(x² + y² + z² - xy - yz - zx)
→ (9)(35 - 23)
→ 9×12
→ 108
Hence,
The value of x³ + y³ + z³ - 3xyz is 108
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