Question

Which shows the correct substitution of the values a, b, and c from the equation -2=-x+x^2-4 into the quadratic formula?

Answer 1

The  correct substitution of the values a, b, and c from the equation -2=-x+x^2-4 into the quadratic formula is that a=1b=-1c-2

Solution:ax^2+bx+c=0x^2-x-2=0a=1b=-1c-2
x=-b+-sqtb^2-4ac all over 2ax=-(-1)+-sqt(-1)^2)-4(1)(-2) all over 2(1)
Answer:x1=2x2=-1

Answer 2

Given the equation:

(1) $-2=-x+ x^{2}-4$

We need to find a, b and c. So, we know that a quadratic equation is given by:

(2) $ax^{2}+bx+c=0$

Then, we need to order the equation (1) and to adjust it to the equation (2), so:

$x^{2}-x-2=0$

So, if we compare these two equations, the conclusion is:

$a=1$
$b=-1$
$c=-2$

(3) $x= \frac{-b\pm \sqrt{b^{2}-4ac}}{2a}$

Substituiting a, b and c into (3):

$x= \frac{-(-1)\pm \sqrt{(-1)^{2}-4(1)(-2)}}{2(1)}$

Finally, the results are two values:

$x_{1}=2$
$x_{2}=-1$