Question

The conjugate of 5–√ + 7 is

Answer 1

Answer:

32

Step-by-step explanation:

$(5 + \sqrt{ - 7} (5 - \sqrt{ - 7} ) =$

$(5 + i \sqrt{ - 7} )(5 - i \sqrt{ - 7} ) =$

$= ( {5)}^{2 - }$

${i}^{2} ( \sqrt{7} ) ^{2} {(a - b) = a }^{2} - b {}^{2}$

$= 25 - ( - 1)7 \: \: ( = i {}^{2} = - 1) = 25 + 7 = 32$