Question

Factorise 49a^2-81b^2​

Answer 1

Answer:

(7a-9b)(7a+9b)

Explanation:

Answer 2

Answer:

(7a + 9b)(7a - 9b)

Explanation:

Using the formula $(a-b)^{2} = (a + b)(a - b)$.

In the question the value of $a^{2}$ is given, but we need the value of $a$, so:

Value of $a$ = $\sqrt{a^2}$ = $\sqrt{49a^2}$ = 7a

Similarly, calculate the value of $b$.

Value of $b$ = $\sqrt{b^2}$ = $\sqrt{81b^2}$ = 9b

Now, substitute the value of $a$ and $b$ in the formula.

$(a-b)^{2} = (a + b)(a - b)$ = (7a + 9b)(7a - 9b)