Algebra and Applications Test 1

© examsiri.com

Question : 26 of 40

Marks: +1, -0

If

a+1/a+1=0 \;(a≠0)

, then the value of

(a^4 - a)

is:

0
1
2
-1

Solution:

We have an expression

(a^4 - a)

= a(a^3 - 1)

= a(a^3 - 1^3)

= a(a - 1)(a^2 + a + 1)

[∵ a^3 - b^3 = (a - b) (a^2 + ab + b^2)]

Also we have

a+1/a+1=0

a^2 + a + 1 = 0

So,

a(a - 1)(a^2 + a + 1) = 0

© examsiri.com

Go to Question:

Prev Question

Next Question