Question

a into a minus 1 minus b into B minus one​

Answer 1

hi there mate ☺
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$step \: by \: step \: explaination$
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$a \times a - 1 - b \times b - 1$
${a}^{2} - 2 - {b}^{2}$
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Hope it helps ✌✌

Answer 2

$a(a - 1) - b(b - 1) \\ {a}^{2} - a - {b}^{2} + b \\ ( {a}^{2} - {b}^{2} ) - (a - b) \\ (a + b)(a - b) - (a - b) \\ (a - b)(a + b - 1)$