**(i) (x – y) ^{2}_{ }– 9**

**(ii) 9(x + y) ^{2} – x^{2}**

**Answer :**

**(i) (x – y)**^{2}_{ }– 9

^{2}

_{ }– 9

(x – y)^{2} – 3^{2}

We know that, a^{2} – b^{2} = (a + b) (a – b)

(x – y + 3) (x – y – 3)

**(ii) 9(x + y)**^{2} – x^{2}

^{2}– x

^{2}

9[(x + y)^{2} – x^{2}]

We know that, a^{2} – b^{2} = (a + b) (a – b)

9[(x + y + x) (x + y – x)]

So, 9(2x + y) y

9y(2x + y)

**More Solutions:**