Question

what is the factor of this trinomial a2 + 4ab – 45b2?

Answer 1

Because it is + then - we know it needs to be in the form ( a + b )( a - b )

Answer 2

I would first look at the coefficient of b^2 which as 45 and write down all the numbers when multiplied will give you 45.

Answer 3

Then look at these numbers and see which two when added will give you 4. And excuse my last post, I should have said find all the products that will give you -45

Answer 4

Let me know if you are still stuck

Answer 5

@ChmE so you multiply all the products that equal to 45 and then add the two that will give you 4?

Answer 6

That is a thought process for solving it. 9,-5 -9,5 1,-45 -1,45 I think thats it. Then you think what numbers, when added will give me 4. you see 9,-5

Answer 7

and if you look at my first post, you see the form it needs to be is consistent with these numbers. So ( a + 9b ) ( a - 5b )

Answer 8

@chme thanks.