Question

expand (3x+2y)(3x-2y)(9x2-4y2)​

Answer 1

Step-by-step explanation:

Given,

3x−2y=5−−−−−−(1) and xy=4−−−−−(2)

squaring (1),

9x

2

+4y

2

−12xy=25

using (2),

9x

2

+4y

2

=25+12×4

=>73

Answer 2

Step-by-step explanation:

Answer

$expand \: = (3x + 2y)(3x - 2y)(9 {x}^{2} - {4y}^{2} )$

$\: \: \implies \bf{(3x + 2y)(3x - 2y)( {9x}^{2} - {4y}^{2} )}$

$\: \implies \bf{(3x(3x - 2y) + 2y(3x - 2y)( {9x}^{2} - {4y}^{2} )}$

$\: \: \implies \bf{( {9x}^{2} - 6xy + 6xy - {4y}^{2} )( {9x}^{2} - {4y}^{2} )}$

$\: \: \implies \bf{(9 {x}^{2} - \cancel{ - 6xy + 6xy} - 4 {y}^{2} )( {9x}^{2} - {4y}^{2} )}$

$\: \: \implies \bf{ ({9x }^{2} - {4y}^{2} )( {9x}^{2} - {4y}^{2} )}$

$\: \implies \bf{ {9x}^{2} ( {9x}^{2} - {4y}^{2} ) - {4y}^{2} ( {9x}^{2} - {4y}^{2}) }$

$\: \implies \bf{ {81x}^{4} - 36 {x}^{2} {y}^{2} - 36 {x}^{2} {y}^{2} - {16y}^{4} }$

$\: \implies \bf{ {81x}^{4} - {16y}^{4} }$

$\: \: \: \pink \bigstar \boxed{ \bf \red{answer \: will \: be \: {81x}^{4} - {16y}^{4} }}$