Question

Choose the correct GCF for the following binomial: 6a^4b^2 + 9a^3^b

Answer 1

r u sure about the second expression?

Answer 2

6a^4b^2 + 9a^3b oops lol here ya go

Answer 3

Alright, best way is to do it in bits.
So, GCF of 6 and 9?

Answer 4

3

Answer 5

Correct, now a^4 and a^3...

Answer 6

they dont have a GCF

Answer 7

Well you can divide each of them by a, right?

Answer 8

No i dont think so i am stuch on this one

Answer 9

a^4 just means a*a*a*a and to divide by a
then you just knock one off to give a*a*a or a^3
So a^4/a would be a^3

In same way, you can divide by a^2, just knock 2 off
So a^4/a^2 = a^2

So what would it be if you divided a^4 by a^3?

Answer 10

its just a right? :)

Answer 11

Right.

Answer 12

So now we can go go back, GCF of a^4 and a^3 ?

Answer 13

so far it is 3a

Answer 14

a^3, yes.

Answer 15

And finally, b^2 and b....?

Answer 16

just b? or is is B^1

Answer 17

Correct, b= b^1 so you just leave out the ^1 part.

So now put the 3 bits together and you have you GCF.

Answer 18

Factor completely: 64a2b3 − 40ab and with this one the answer is
4(8b2 − 10ab)

Answer 19

This is a similar idea, you want to find the biggest bit you can "take out of" both parts to put in front of the bracket.

So, start with the numbers, GCF of 64 and 40?

Answer 20

8?

Answer 21

Right.
a^2 and a?
b^3 and b?

Answer 22

a and b^2

Answer 23

a is right.
But b^2 wont divide into b, will it? So that is just b as well.

So you can take out 8ab( )

What goes in the brackets?

Answer 24

Once you done about 20 of these you will just do it without even thinking...:-)

Answer 25

r u OK now?

Answer 26

(8ab^2 − 5)?