Question

prove that 2√3-7 is a rational number​

Answer 1

Answer:

$2 \sqrt{3 - 7} = 2 \sqrt{ - 4} = 2 \times ±2 = ±4 \\ \\ note \: -> {2}^{2} \: and \: { - 2}^{2} is \: same \: that \: is \: 4 \\ that \: is \: why \\ \: we \: use \: ± \: sign \: before \: the \: square \: root \: of \: anything \: \\ because \: it \: can \: be \: positive \: or \: negative$