Question

Answer 1

\(9x^2-16y^2+15x-20y\)
\(=\left(3x-4y\right)\left(3x+4y\right)+5\left(3x-4y\right)\)

\(=\left(3x-4y\right)\left(3x+4y+5\right)\)

Answer 2

`#3107.101107`

`9x^2 - 16y^2 + 15x - 20y`

`= (3x)^2 - (4y)^2 + (15x - 20y)`

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

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

____

Sử dụng hđt:

`A^2 - B^2 = (A - B)(A + B).`