Question

factorise 81 x square /4-y square/49​

Answer 1

81x²/4 - 4y²/49

= (9x/2)²-(2x/7)²

= (9x/2 + 2x/7)(9x/2 - 2x/7) Ans.

Answer 2

$\star\:\:\:\bf\large\underline\blue{Question:-}$

• Factorise $\frac{81 {x}^{2} }{4} - \frac{ {y}^{2} }{49}$

$\star\:\:\:\bf\large\underline\blue{Solution:-}$

$\frac{81 {x}^{2} }{4} - \frac{ {y}^{2} }{49}$

$=( \frac{9x}{2})^{2} - {( \frac{y}{7} )}^{2}$

$= ( \frac{9x}{2} + \frac{y}{7} )( \frac{9x}{2} - \frac{y}{7} )$

$\star\:\:\:\bf\large\underline\blue{Answer:-}$

• Factorised form is $= ( \frac{9x}{2} + \frac{y}{7} )( \frac{9x}{2} - \frac{y}{7} )$

$\star\:\:\:\bf\large\underline\blue{Identity\:Used:-}$

• ${x}^{2} - {y}^{2} = (x + y)(x - y)$