Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If x = 222, y = 223 and z = 224, then find the value of $x^3 + y^3 + z^3 - 3xyz$.

Options:

2007

2004

2006

2005

Correct Answer:

2007

Explanation:

x = 222,

y = 223

z = 224 

x3 + y3 + z3 - 3xyz = \(\frac{1}{2}\)(x + y + z)[(x - y)2 + (y - z)2 + (z - x)2]

= x3 + y3 + z3 - 3xyz = \(\frac{1}{2}\)(222 + 223 + 224)[(222 - 223)2 + (223 - 224)2 + (224 - 222)2]

= x3 + y3 + z3 - 3xyz = \(\frac{1}{2}\)(669)[(1) + (1) + (4)]

= x3 + y3 + z3 - 3xyz = 3 × 669 

= x3 + y3 + z3 - 3xyz = 2007