Question

Perform the indicated operation.
(3a^2 - 7xy)(3a^2 + 7xy)

​

Answer 1

$\quad \huge \quad \quad \boxed{ \tt \:Answer }$

$\qquad \tt \rightarrow \: (3 {a}^{2} - 7xy)(3 {a}^{2} + 7xy) = 9 {a}^{ 4 } - 49 {x}^{2} {y}^{2}$

____________________________________

$\large \tt Solution \: :$

$\qquad \tt \rightarrow \: (3 {a}^{2} - 7xy)(3 {a}^{2} + 7xy)$

$\qquad \tt \rightarrow \:(3 {a}^{2} \sdot3 {a}^{2} ) + (3a {}^{2} \sdot7xy) - (7xy \sdot3 {a}^{2} ) - (7xy \sdot7xy)$

$\qquad \tt \rightarrow \:9 {a}^{4} + 21a {}^{2} xy- 21 {a}^{2} xy - 49 {x}^{2} {y}^{2}$

$\qquad \tt \rightarrow \: 9 {a}^{ 4 } - 49 {x}^{2} {y}^{2}$

or

Apply property :

$\qquad \tt \rightarrow \: (p + q)(p - q) = {p}^{2} - {q}^{2}$

Answered by : ❝ AǫᴜᴀWɪᴢ ❞