Question

How do you evaluate `-a ( a ^2 + 2a - 1)` for a = 2?

Answer 1

-14

Explanation:

In substitution, we replace something for something else, in this case anytime we see `a`, we put a 2 there. Applying this:
`-2(2^2+2(2)-1)=-2(4+4-1)`
`=-2(7)`
`=-14`

Answer 2

`-14`

Explanation:

`color(blue)(-a(a^2+2a-1)` `"for"` `a=2`

Now substitute the value of `a` into the equation

`rarrunderbrace(-a)(underbrace(a^2)+2underbracea-1)`

`rarr-2(2^2+2(2)-1)`

`rarr-2(4+4-1)`

`rarr-2(7)`

`color(green)(rArr-14`