Question

How 2 +1 -2 ×1 √2=(√2-1)^2 ?

Answer 1

by bodmas
$2 + 1 - 2 \times 1 \sqrt{2} = (\sqrt{2} - 1) {}^{2} \\ using \: the \: formula \\ {a}^{2} + {b}^{2} - 2ab = here \: {a}^{2} = \sqrt{2} ^{2} and \: {b}^{2} = {1}^{2} and \: 2ab = 2 \times 1 \times \sqrt{2} \\ we \: know \: that \: \\ {a}^{2} + {b}^{2} + 2ab = (a + b) {}^{2} \\ so \:$
$2 + 1 - 2 \times 1 \sqrt{2} = (\sqrt{2} - 1) {}^{2}$

hope it helps mark it brainliest