Question

expand the following by using identities ( 3a -7 ) 2
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Answer 1

$\huge \sf \red{Answer}$

${(3a - 7)}^{2}$

☞$by \: using \: identity \: {(a - b)}^{2} = {a}^{2} - 2ab + {b}^{2}$

$= {(3a)}^{2} - 2(3a)(7) + {(7)}^{2}$

$= 9 {a}^{2} - 42a + 49$

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