Question

Evaluate the expression for the given value of the variable. | − 4 b − 8 | + ∣ ∣ − 1 − b 2 ∣ ∣ + 2 b 3 ; b = − 2

Answer 1

The value of expression at b= -2 is -11

Explanation:

Given: Expression =
`\left |-4b-8\right |+\left | -1-b^2\right |+2b^3`

To find: Value of given expression when b = -2

Expression

`\left |-4b-8\right |+\left | -1-b^2\right |+2b^3`

Put, b = -2 in above expression. we get

⇒
`\left |-4*(-2)-8\right |+\left | -1-(-2)^2\right |+2(-2)^3`

⇒
`\left |8-8\right |+\left | -1-4\right |+2*(-8)`

⇒
`\left |0\right |+\left | -5\right |+(-16)`

⇒
`0+5-16`

⇒ -11

Therefore, The value of expression at b= -2 is -11

Answer 2

-11

Explanation:

The given expression is:

`|-4b-8|+|-1-b^2|+2b^3`

=
`|-(4b+8)|+|-(1+b^2)|+2b^3`

=
`4b+8+1+b^2+2b^3`

=
`4b+9+b^2+2b^3`

Substituting the value of b=-2 in above expression, we get

=
`4(-2)+9+(-2)^2+2(-2)^3`

=
`-8+9+4-16`

=
`-11`

Thus, the value of the given expression is -11.