Determine Whether the Given Values Are Solutions of the Equation

Question:

Determine whether the given values are solution of the given equation or not:

\[ a^2x^2-3abx+2b^2=0 \]

(i) \(x=\frac{a}{b}\)
(ii) \(x=\frac{b}{a}\)

Solution

A value of \(x\) is a solution if it makes the left-hand side equal to zero.

Checking \(x=\frac{a}{b}\)

Substitute \(x=\frac{a}{b}\):

\[ a^2\left(\frac{a}{b}\right)^2-3ab\left(\frac{a}{b}\right)+2b^2 \]

\[ =\frac{a^4}{b^2}-3a^2+2b^2 \]

This expression is not identically equal to zero.

Hence, \[ x=\frac{a}{b} \] is not a solution in general.

Checking \(x=\frac{b}{a}\)

Substitute \(x=\frac{b}{a}\):

\[ a^2\left(\frac{b}{a}\right)^2-3ab\left(\frac{b}{a}\right)+2b^2 \]

\[ =b^2-3b^2+2b^2 \]

\[ =0 \]

Therefore, \[ x=\frac{b}{a} \] is a solution of the equation.

Answer

\[ \boxed{x=\frac{a}{b}\text{ is not a solution, whereas }x=\frac{b}{a}\text{ is a solution}} \]

Alternatively, factorizing:

\[ a^2x^2-3abx+2b^2 =(ax-b)(ax-2b) \]

The solutions are \[ x=\frac{b}{a} \quad\text{and}\quad x=\frac{2b}{a}. \]

Hence only \[ \boxed{x=\frac{b}{a}} \] among the given values satisfies the equation.

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