Question

Gấp

\[ 7 - 2\sqrt{x^2 + 16} = -3 \]

Answer 1

\(7-2\sqrt{x^2+16}=-3\)

\(2\sqrt{x^2+16}=7-\left(-3\right)\)

\(2\sqrt{x^2+16}=10\)

\(\sqrt{x^2+16}=10:2\)

\(\sqrt{x^2+16}=5\)

\(x^2+16=25\)

\(x^2=25-16\)

\(x^2=9\)

\(x=-3\) hoặc \(x=3\)

Vậy \(x=-3;x=3\)