Question
Simplify by using formula :$(a + b - c) (a - b + c)$
✓
Answer
$(a + b - c) (a - b + c)$
$= (a + b - c) [a - (b - c)]$
$= (a)^2 - (b - c)^2$
$($using identity $: (a + b) (a - b) = a^2 - b^2)$
$= a^2 - (b^2 + c^2 - 2bc)$
$= a^2- b^2- c^2 + 2bc.$
$= (a + b - c) [a - (b - c)]$
$= (a)^2 - (b - c)^2$
$($using identity $: (a + b) (a - b) = a^2 - b^2)$
$= a^2 - (b^2 + c^2 - 2bc)$
$= a^2- b^2- c^2 + 2bc.$
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