What must be added to xy to make it yx?
y2−x2yx
y−xy2x2
xyx+y
x2−y2x2+y2
Let k be the required term which needs to be added to xy to make it equal to yx. xy+k=yx ⇒k=yx−xy=y2−x2yx ∴ Term which needs to be added =y2−x2yx.
What must be added to xy+3x−2y to get 7x+5y?