factor 4x^2+17xy-15y^2?

Question

I am hitting a wall here; can anyone help?

Answer 1

Please read the answers to the same question you've asked a while back, or maybe you haven't realised that people HAVE been answering your question.

Answer 2

4x² + 17xy - 15y² =

The middle term is + 17xy

Find the sum of the middle term

Multiply the first term 4 times the last term 15 equals 60and factor

factors of 60=

1 x 60
2 x 30
3 x 20. . .<=. .use these factors
4 x 15
5 x 12
6 x 10

+ 20 - 3 satisfy the sum of the middle term

insert + 20xy and - 3xy into the equation

4x² + 17xy - 15y²

4x² + 20xy - 3xy - 15y²

4x(x + 5y ) - 3y(x + 5)

(4x - 3y)(x + 5)

- - - - - - -s-

Answer 3

I do not understand why you keep asking this question. The answers you have been given which say
(4x - 3y)(x + 5y)
are all correct. Factorisation is largely trial and error. You have to find two pairs of numbers:
(a) one pair which multiply to give 4 for the coefficient of x. That could only be 4 and 1 or 2 and 2.
(b) one pair which multiply to give -15 for the coefficient of y. That could be 5 and -3 or 15 and -1, or either of these pairs with the signs switched.
You have to experiment with the combinations until you find a combination which gives the right value and sign for the xy term.

Answer 4

42

Answer 5

(x+ 5y)(4x - 3y)