Question

корень из 7-х=4 оладжадав

Answer 1

корень 7-х ^2=4^2
7-x=16
-x=9
x=-9

Answer 2

$\sqrt{7-x}=4\\( \sqrt{7-x})^2=4^2\\7-x=16\\x=7-16\\x=-9\\\\ \sqrt{7-(-9)}= \sqrt{7+9}= \sqrt{16}=4\\\\x=-9$