Question

Tim x biết:

a) \(8\sqrt{x}-3\sqrt{\frac{4}{81}}=5,2\)

b)\(12-3x^2=10+\sqrt{\frac{25}{16}}\)

Answer 1

a)\(8\sqrt{x}-3\sqrt{\frac{4}{81}}=5,2\)

\(\Rightarrow8\sqrt{x}-3.\frac{2}{9}=5,2\)

\(\Rightarrow8\sqrt{x}-\frac{2}{3}=5,2\)

\(\Rightarrow8\sqrt{x}=5,2+\frac{2}{3}\)

\(\Rightarrow8\sqrt{x}=\frac{40}{3}\)

\(\Rightarrow\sqrt{x}=\frac{40}{3}:8\)

\(\Rightarrow\sqrt{x}=\frac{5}{3}\)

\(\Rightarrow x=\frac{25}{9}\)

b)\(12-3x^2=10+\sqrt{\frac{25}{16}}\)

\(\Rightarrow12-3x^2=10+\frac{5}{4}\)

\(\Rightarrow12-3x^2=11,25\)

\(\Rightarrow3x^2=12-11,25\)

\(\Rightarrow3x^2=0,75\)

\(\Rightarrow x^2=0,25\)

\(\Rightarrow x=\sqrt{0,25}\)

\(\Rightarrow x=0,5\)