Question

Rounded to the nearest hundredth , what is the positive solution to the quadratic equation 0=2x^2+3x-8

Answer 1

The positive solution to the quadratic equation $2 x^{2}+3 x-8=0$ is x = 1.39

Solution:

Given quadratic equation is $2 x^{2}+3 x-8=0$

The general quadratic equation is of form:

$a x^{2}+b x+c=0$

Now comparing the general equation with the given equation we get

a = 2 , b = 3 and c = -8

The formula to determine roots of the quadratic equation is:

$x=\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}$

On plugging in vlaues, we get

$x=\frac{-3 \pm \sqrt{3^{2}-4 \times 2 \times(-8)}}{2 \times 2}$

$\mathrm{x}=\frac{-3 \pm \sqrt{9-(-64)}}{4}$

On solving we get,

$\begin{array}{l}{\mathrm{x}=\frac{-3 \pm \sqrt{9+64}}{4}} \\\\ {\mathrm{x}=\frac{-3 \pm \sqrt{73}}{4}}\end{array}$

$\mathrm{x}=\frac{-3+\sqrt{73}}{4} \text { OR } \mathrm{x}=\frac{-3-\sqrt{73}}{4}$

x = 1.39  OR  x = -2.89  

Hence , the positive solution to the quadratic equation  is x = 1.39