Evaluate x^2+2x if x=-2

Question

uri · Answer

x^2+2x if x=-2
Put -2 where there is x
So,
(-2)^2+2(-2)

Can you solve it?

uri · Answer

Wait it's -2^ no bracket.

uri · Answer

-2^2*

anonymous · Answer

not at all

phi · Answer

uri you were correct the first time:

$$ x^2+2x $$if x=-2
Put -2 where there is x
So,
(-2)^2+2(-2)

another way to think of it:  factor out an x to get
$$ x(x+2) $$
sub in -2 for x:
$$ -2(-2+2) $$

uri · Answer

Oh all right i was confused :) Thanks.

phi · Answer

@cynthia_franco 

uri told you the rule:  everywhere you see x,  erase the x and put in -2

you get
$$ (-2)^2+2(-2)  $$

remember that (-2)^2  means -2 * -2, so this is the same as
$$ -2 \cdot -2 + 2 \cdot -2 $$
can you simplify that ?

phi · Answer

you do it in steps:

first what is -2 times -2 ?
then do   2 times -2

then add those two numbers