Find the Value of k for which the Given Value is a Solution

Question:

Find the value of \(k\) for which the given value is a solution of the equation:

\[ 7x^2+kx-3=0 \]

Given, \[ x=\frac{2}{3} \]

Solution

Since \(x=\frac{2}{3}\) is a solution, it must satisfy the equation.

Substituting \(x=\frac{2}{3}\) into \[ 7x^2+kx-3=0, \] we get

\[ 7\left(\frac{2}{3}\right)^2+k\left(\frac{2}{3}\right)-3=0 \]

\[ 7\cdot\frac{4}{9}+\frac{2k}{3}-3=0 \]

\[ \frac{28}{9}+\frac{2k}{3}-\frac{27}{9}=0 \]

\[ \frac{1}{9}+\frac{2k}{3}=0 \]

Multiplying both sides by 9:

\[ 1+6k=0 \]

\[ 6k=-1 \]

\[ k=-\frac{1}{6} \]

Answer

Therefore, the required value of \(k\) is

\[ \boxed{k=-\frac{1}{6}} \]

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