Question

Select and use the most direct method to solve 2x(x + 1.5) = -1. Describe and justify the methods you used to solve the quadratic equation

Answer 1

Step-by-step explanation:

Given that,

A quadratic equation,

2x(x + 1.5) = -1

We need to solve the quadratic equation. Firstly we need to simplify the above equation to form it as $ax^2+bx+c=0$.

So,

$2x^2+3x=-1\\\\2x^2+3x+1=0$

Here, a = 2, b = 3 and c = 1

The roots of the given equation can be given by :

$x=\dfrac{-b\pm \sqrt{b^2-4ac} }{2a}$

Putting all the values we get :

$x=\dfrac{-b\pm \sqrt{b^2+4ac} }{2a}, \dfrac{-b\pm \sqrt{b^2-4ac} }{2a}\\\\x=\dfrac{-3\pm \sqrt{3^2+4(2)(1)} }{2(2)}, \dfrac{-3\pm \sqrt{3^2-4(2)(1)} }{2(2)}\\\\x=\dfrac{-3+1}{4}, \dfrac{-3-1}{4}\\\\x=-\dfrac{1}{2}, -1$

So, the roots of the given equation is -1/2 and -1.