Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If x = a (b - c)

y = b (c - a)

z = c (a - b)

then find the value of \(\left[\frac{(x+y)\;(y+z)\;(z+x)}{5xyz}\right]\)

Options:

-\(\frac{1}{5}\)

\(\frac{3}{5}\)

1

\(\frac{1}{5}\)

Correct Answer:

-\(\frac{1}{5}\)

Explanation:

x = ab - ac

y = bc - ba

z = ca - cb

⇒ x + y + z = ab - ac + bc - ba +  ca - cb = 0

So,

⇒ x + y = -z

⇒ y + z = -x

⇒ z + x = -y

Put the values:

⇒ \(\left[\frac{(x+y)\;(y+z)\;(z+x)}{5xyz}\right]\) = \(\frac{(-x)×(-y)×(-z)}{5xyz}\)

-\(\frac{1}{5}\)