Test Index

RRB NTPC Mains or Stage 2 Model Paper 9 with solutions

© examsnet.com

Question : 9 of 120

Marks: +1, -0

If

x^2 + y^2 + 2x + 1 = 0

, then the value of

x^{31} + y^{35}

is

– 1
0
1
2

Solution:

Concept:

A sum of squares is zero only when each square term is zero.

Explanation:

Given:

x^2 + y^2 + 2x + 1 = 0

.

Rewrite as

x^2 + 2x + 1 + y^2 = 0

.

So,

(x+1)^2 + y^2 = 0

.

Since squares cannot be negative, both terms must be zero.

Thus,

x+1=0

and

y=0

.

So,

x=-1

and

y=0

.

Now,

x^{31}+y^{35}=(-1)^{31}+0^{35}

.

(-1)^{31}=-1

and

0^{35}=0

.

Therefore,

x^{31}+y^{35}=-1

.

Answer:

-1

© examsnet.com

Go to Question:

Prev Question

Next Question