[-4b-8]+[-1-b^2]+2b^3; b=-2
please can someone explain
if all you have to do is evaluate the expression when b = -2, then the value is
[-4b-8]+[-1-b^2]+2b^3
[-4(-2)-8]+[-1-(-2)^2]+2(-2)^3
[8-8]+[-1-4]+2(-8)
0 - 5 - 16
-21
complicated but I think I understand thanks so much
Certainly! To evaluate the expression [-4b-8]+[-1-b^2]+2b^3 when b=-2, you need to substitute -2 in the place of b in the expression and then simplify.
Let's start by replacing b with -2:
[-4(-2)-8]+[-1-(-2)^2]+2(-2)^3
Now we can simplify each term step by step:
First, evaluate -4(-2), which gives us 8:
[8-8]+[-1-(-2)^2]+2(-2)^3
Next, calculate (-2)^2, which is 4:
[8-8]+[-1-4]+2(-2)^3
Now simplify the subtraction -1-4, which gives us -5:
[8-8]+[-5]+2(-2)^3
Next, evaluate (-2)^3, which is -8:
[8-8]+[-5]+2(-8)
Now, simplify 2(-8), which gives us -16:
[8-8]+[-5]+(-16)
Next, calculate the subtraction 8-8, which gives us 0:
[0]+[-5]+(-16)
Finally, add the remaining terms: 0 + (-5) + (-16), which gives us -21:
-5 + (-16) = -21
Therefore, the simplified expression is -21 when b = -2.