Multiply $(2 a - 7)$ and $(2 a - 7)$ .

4 a^{2} - 28 a + 49

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4 a^{2} + 28 a + 49

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2 a^{2} + 28 a + 49

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2 a^{2} - 28 a + 49

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Solution

The correct option is A $4 a^{2} - 28 a + 49$
$(2 a - 7) (2 a - 7)$
Using ,
$(a - b)^{2} = a^{2} - 2 a b + b^{2}$ , we get the above equation.
$= (2 a - 7)^{2}$
$= (2 a)^{2} - 2 \times 2 a \times 7 + 7^{2}$
$= 4 a^{2} - 28 a + 49$

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