What must be added to xy+3x−2y to get 7x+5y?
4x + 7y - xy
Let the required algebraic expression be P.
∴P+(xy+3x−2y)=7x+5y
⇒P=7x+5y−(xy+3x−2y)
⇒P=7x+5y−xy−3x+2y [Opening brackets]
Group like terms together.
⇒P=(7x−3x)+(5y+2y)−xy
⇒P=4x+7y−xy