Answer
the solution set is\[\left\{ -2\pm \sqrt{11} \right\}\].
Work Step by Step
The given equation can be written as \[{{x}^{2}}+4x-7=0\].
Compare the given equation with the equation\[a{{x}^{2}}+bx+c=0\].
Here,\[a=1,\,\,b=4,\text{ and }c=-7\].
Now put these values in the quadratic formula: \[x=\frac{-b\pm \sqrt{{{b}^{2}}-4ac}}{2a}\]
That is,
\[\begin{align}
& x=\frac{-4\pm \sqrt{{{\left( 4 \right)}^{2}}-4\times 1\times \left( -7 \right)}}{2\times 1} \\
& =\frac{-4\pm \sqrt{16+28}}{2} \\
& =\frac{-4\pm \sqrt{44}}{2} \\
& =-2\pm \sqrt{11}
\end{align}\]
Hence, the solution set is\[\left\{ -2\pm \sqrt{11} \right\}\].
