Add the following ( 2x^2 + 5xy ) + ( 4x - 7xy ) - 2x^2.

When we add or subtract polynomials, we have to find the
variables and exponents that match.

First, we'll remove the
brackets:

2x^2 + 5xy + 4x - 7xy -
2x^2

Now, we'll search for the terms that have matching
variables.

We notice that 2x^2 and -2x^2 have the same
variables and opposite coefficients, so we'll eliminate the
terms.

2x^2 - 2x^2 = 0

Now,
we'll combine the terms that have the variables x*y:

5xy -
7xy = -2xy

We notice that the term 4x is alone and we'll
add it to the final result.

The result of
adding the polynomials
is:

(2x^2 + 5xy) + (4x - 7xy)
- 2x^2 = 4x - 2xy