Question

If a3 + 3a2 + 9a = 1, then what is the value of a3 + (3/a)?

Answer 1

(x+1)(x+2)=(x+1)(x+2)=(x)(x)+(x)(2)+(1)(x)+(1)(2)=x2+2x+x+2=x2+3x+2

Answer 2

Answer:

The value of the expression:

$a^3+\dfrac{3}{a}=28$

Step-by-step explanation:

We are given the expression as:

$a^3+3a^2+9a=1$

Now on taking 'a' common we get:

$a(a^2+3a+9)=1\\\\a^2+3a+9=\dfrac{1}{a}$

( since on dividing both side by a)

$\dfrac{3}{a}=3\times (a^2+3a+9)\\\\\\\dfrac{3}{a}=3a^2+9a+27\\\\a^3+\dfrac{3}{a}=a^3+3a^2+9a+27\\\\\\a^3+\dfrac{3}{a}=1+27$

( since using the value of the original expression)

$a^3+\dfrac{3}{a}=1+27=28$

Hence, the value of the expression:

$a^3+\dfrac{3}{a}=28$