x^2+9y^2-25m^2-16n^2+6xy+40mn
(x+3y+5m-4n)(x+3y-5m+4n)
Looks good to me.
The expression you've provided is a polynomial expression with multiple terms. To simplify it, you can collect like terms and combine them.
Starting with the expression: x^2 + 9y^2 - 25m^2 - 16n^2 + 6xy + 40mn
First, let's group the terms with similar variables:
(x^2 + 6xy) + (9y^2) + (-25m^2 + 40mn) + (-16n^2)
Now, we can simplify each group of terms individually:
Group 1: (x^2 + 6xy)
This group contains terms with variables x and y. To combine them, we can factor out the common variable:
x(x + 6y)
Group 2: (9y^2)
This group has only one term, so there is nothing to simplify.
Group 3: (-25m^2 + 40mn)
This group contains terms with variables m and n. To combine them, we can factor out the common variable:
-5m(5m - 8n)
Group 4: (-16n^2)
This group has only one term, so there is nothing to simplify.
Now, we can combine all the simplified groups:
x(x + 6y) + 9y^2 - 5m(5m - 8n) - 16n^2
And that is the simplified form of the given expression, x^2 + 9y^2 - 25m^2 - 16n^2 + 6xy + 40mn.