Solve for: 15/2.5

Expression: $4{x}^{2}+8x+6=0$

Divide both sides of the equation by $2$

$2{x}^{2}+4x+3=0$

Identify the coefficients $a$, $b$ and $c$ of the quadratic equation

$\begin{array} { l }a=2,& b=4,& c=3\end{array}$

Substitute $a=2$, $b=4$ and $c=3$ into the quadratic formula $x=\frac{ -b\pm\sqrt{ {b}^{2}-4ac } }{ 2a }$

$x=\frac{ -4\pm\sqrt{ {4}^{2}-4 \times 2 \times 3 } }{ 2 \times 2 }$

Evaluate the power

$x=\frac{ -4\pm\sqrt{ 16-4 \times 2 \times 3 } }{ 2 \times 2 }$

Calculate the product

$x=\frac{ -4\pm\sqrt{ 16-24 } }{ 2 \times 2 }$

Multiply the numbers

$x=\frac{ -4\pm\sqrt{ 16-24 } }{ 4 }$

Calculate the difference

$x=\frac{ -4\pm\sqrt{ -8 } }{ 4 }$

The square root of a negative number does not exist in the set of real numbers

$x\notin ℝ$