In each of the following, determine whether the given numbers are roots of the given equations or not; (i)

    \[{{\mathbf{x}}^{\mathbf{2}}}~\text{ }\mathbf{5x}\text{ }+\text{ }\mathbf{6}\text{ }=\text{ }\mathbf{0};\text{ }\mathbf{2},\text{ }-\mathbf{3}\]

(ii)

    \[\mathbf{3}{{\mathbf{x}}^{\mathbf{2}}}~\text{ }\mathbf{13x}\text{ }\text{ }\mathbf{10}\text{ }=\text{ }\mathbf{0};\text{ }\mathbf{5},\text{ }-\mathbf{2}/\mathbf{3}\]

In each of the following, determine whether the given numbers are roots of the given equations or not; (i)

    \[{{\mathbf{x}}^{\mathbf{2}}}~\text{ }\mathbf{5x}\text{ }+\text{ }\mathbf{6}\text{ }=\text{ }\mathbf{0};\text{ }\mathbf{2},\text{ }-\mathbf{3}\]

(ii)

    \[\mathbf{3}{{\mathbf{x}}^{\mathbf{2}}}~\text{ }\mathbf{13x}\text{ }\text{ }\mathbf{10}\text{ }=\text{ }\mathbf{0};\text{ }\mathbf{5},\text{ }-\mathbf{2}/\mathbf{3}\]

(i) 

    \[{{\mathbf{x}}^{\mathbf{2}}}~\text{ }\mathbf{5x}\text{ }+\text{ }\mathbf{6}\text{ }=\text{ }\mathbf{0};\text{ }\mathbf{2},\text{ }-\mathbf{3}\]

Let us substitute the given values in the expression and check,

When,

    \[\begin{array}{*{35}{l}} x\text{ }=\text{ }2  \\ {{x}^{2}}~\text{ }5x\text{ }+\text{ }6\text{ }=\text{ }0  \\ {{\left( 2 \right)}^{2}}~\text{ }5\left( 2 \right)\text{ }+\text{ }6\text{ }=\text{ }0  \\ 4\text{ }\text{ }10\text{ }+\text{ }6\text{ }=\text{ }0  \\ 0\text{ }=\text{ }0  \\ \therefore x\text{ }=\text{ }0  \\ \end{array}\]

When,

    \[\begin{array}{*{35}{l}} x\text{ }=\text{ }-3  \\ {{x}^{2}}~\text{ }5x\text{ }+\text{ }6\text{ }=\text{ }0  \\ {{\left( -3 \right)}^{2}}~\text{ }5\left( -3 \right)\text{ }+\text{ }6\text{ }=\text{ }0  \\ 9\text{ }+\text{ }15\text{ }+\text{ }6\text{ }=\text{ }0  \\ 30\text{ }=\text{ }0  \\ \therefore x\text{ }\ne \text{ }0  \\ \end{array}\]

Hence, the value

    \[x\text{ }=2\]

is the root of the equation.

And value

    \[x\text{ }=\text{ }-3\]

is not a root of the equation.

(ii)

    \[\mathbf{3}{{\mathbf{x}}^{\mathbf{2}}}~\text{ }\mathbf{13x}\text{ }\text{ }\mathbf{10}\text{ }=\text{ }\mathbf{0};\text{ }\mathbf{5},\text{ }-\mathbf{2}/\mathbf{3}\]

Let us substitute the given values in the expression and check,

When,

    \[\begin{array}{*{35}{l}} x\text{ }=\text{ }5  \\ 3{{x}^{2}}~\text{ }13x\text{ }\text{ }10\text{ }=\text{ }0  \\ 3{{\left( 5 \right)}^{2}}~\text{ }13\left( 5 \right)\text{ }\text{ }10\text{ }=\text{ }0  \\ 3\left( 25 \right)\text{ }\text{ }65\text{ }\text{ }10\text{ }=\text{ }0  \\ 75\text{ }\text{ }75\text{ }=\text{ }0  \\ 0\text{ }=\text{ }0  \\ \therefore x\text{ }=\text{ }0  \\ \end{array}\]

When,

    \[\begin{array}{*{35}{l}} x\text{ }=\text{ }-2/3  \\ 3{{x}^{2}}~\text{ }13x\text{ }\text{ }10\text{ }=\text{ }0  \\ 3{{\left( -2/3 \right)}^{2}}~\text{ }13\left( -2/3 \right)\text{ }\text{ }10\text{ }=\text{ }0  \\ 4/9\text{ }+\text{ }26/3\text{ }\text{ }10\text{ }=\text{ }0  \\ 4/3\text{ }+\text{ }26/3\text{ }\text{ }10\text{ }=\text{ }0  \\ 30/3\text{ }\text{ }10\text{ }=\text{ }0  \\ 10\text{ }\text{ }10\text{ }=\text{ }0  \\ \therefore x\text{ }=\text{ }0  \\ \end{array}\]

Hence, the value

    \[x\text{ }=\text{ }5,\text{ }-2/3\]

are the roots of the equation.