Question

Evaluate

3t(t+2)-3t^2 for t=19
and
Simplifiy
-(3a-2b)-3(-a-b)

I've already completed them on homework but got them wrong, can someone explain them to me please?

Answer 1

Can you show me what you did for the first one?
So I can check it please.

Answer 2

I filled in the t's. So got the equation 3(19)(19+2)-3(19)^2
multiplied 3(19) and 3(19)^2 and got the equation 57(19+2)- 3249
I then used the distributive property gettng 1083+114-3249 and got my final answer -2052.
My book says its 114.

Answer 3

hmmm... I'm getting 3(19)^2=1083 not 3249

Answer 4

Okay, yes I got that the second time when I entered it into my calculator just like that.

Answer 5

So it should be 57(19+2)-1083
right?

Answer 6

yes ma'am.

Answer 7

Now you were suppose to apply ordered of operations here
but for this one it won't end up to matter so far (but you need to be extremely careful with the next steps you take)
So Now going back to order of operations
It tells us to do what is in the grouping symbols which is 19+2

Answer 8

19+2=?

Answer 9

1197-1083=114!! :) thank you! can you help with the second one? Please & Thank you.

Answer 10

lol oh you got it
that was quick
ok sure

Answer 11

-(3a-2b)-3(-a-b)


Do you remember the distributive property?

Answer 12

Yes, and I get -3a--2b-4a-3b.

Answer 13

x(r+s)=xr+xs <----> Distributive Property

Answer 14

Ok and --=+

Answer 15

And also the second pair you multiply a little wrong

Answer 16

so it should be 2b? not -2b?

Answer 17

We have -3(-a-b)