Question

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

Answer 1

x^2+2x if x=-2
Put -2 where there is x
So,
(-2)^2+2(-2)

Can you solve it?

Answer 2

Wait it's -2^ no bracket.

Answer 3

-2^2*

Answer 4

not at all

Answer 5

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:
\[ -2(-2+2) \]

Answer 6

Oh all right i was confused :) Thanks.

Answer 7

@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 ?

Answer 8

you do it in steps:

first what is -2 times -2 ?
then do 2 times -2

then add those two numbers