Question

How do you evaluate this expression

|-4b-8|+|1-b^2|+2b^3;b=2

Answer 1

for an absolute value expression, once you remove the bars, anything inside comes out as positive.

`\bf |-4b-8|+|1-b^2|+2b^3\implies \stackrel{b=2}~~+~~2(2)^3 \\\\\\ |-8-8|~~+~~|1-4|~~+~~2(8)\implies |-16|~~+~~|-3|~~+~~16 \\\\\\ 16~~+~~3~~+~~16\implies \blacktriangleright 35 \blacktriangleleft`

Answer 2

Answer: -11

Explanation:

|-4b-8| + |-1-b^2| + 2b^3; b = -2

|-4(-2)-8| + |-1-(-2)^2| + 2(-2)^3

= |8-8| + |-1-4| + 2(-8)

= 0 + 5 - 16

= -11

or

|-4b-8| + |-1-b^2| + 2b^3 ; b=-2

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

=| 8 - 8| + | -1 - 4| + 2(-8)

= | 0 | + |-5| - 16

=0 + 5 - 16

= - 11

Either way your answer is still -11.