Question

Tìm x:

 a) \(x^3+2=-62\)

 b) \(215-x^2=115\)

Answer 1

a)\(x^3+2=-62\)

\(\Leftrightarrow x^3=-62-2\)

\(\Leftrightarrow x^3=-64=\left(-4\right)^3\)

\(\Leftrightarrow x=-4\)

b)\(215-x^2=115\)

\(\Leftrightarrow x^2=215-115\)

\(\Leftrightarrow x^2=100=10^2=\left(-10\right)^2\)

\(\Leftrightarrow x=10\) hoặc \(x=-10\)

Answer 2

b, 215-x²=115

<=>x²=215-115

<=>x²=100

<=> x=10