Question

Factor the Trinomial a^2-a-20

Answer 1

Think of two numbers: if you multiply them you get -20
If you add them you get -1

Answer 2

0?

Answer 3

That is only 1 number.

Answer 4

0 and -20

Answer 5

0 multiplied by -20 is 0

Answer 6

Think of two numbers: if you multiply them you get -20

Answer 7

Would 3 x 6 work?

Answer 8

nope

Answer 9

Why not?

Answer 10

when you multiply them they equal 18

Answer 11

Or more importantly...when you multiply them you do NOT get -20

Answer 12

So give some number pairs whose product IS -20

Answer 13

-4,-5

Answer 14

4,-5!

Answer 15

Yes. The last pair. So what are the factors?

Answer 16

(X+4)(X-5)

Answer 17

or a

Answer 18

Very good. You are very smart.

Answer 19

thank you!

Answer 20

yw