C-11-Q069mediumsingle_mcqab=cd\dfrac{a}{b}=\dfrac{c}{d}ba=dc হলে ac+bdac−bd=?\dfrac{ac+bd}{ac-bd} = ?ac−bdac+bd=?aa2+b2a2−b2\dfrac{a^2+b^2}{a^2-b^2}a2−b2a2+b2ba2−b2a2+b2\dfrac{a^2-b^2}{a^2+b^2}a2+b2a2−b2ca+ba−b\dfrac{a+b}{a-b}a−ba+bdc+dc−d\dfrac{c+d}{c-d}c−dc+d