Question

Michele correctly solved a quadratic equation using the quadratic formula as shown below.

Which could be the equation Michele solved?

Answer 1

Look at the picture

Answer 2

The original equation must have been:

`7x^(2) -5x-2=0`

Explanation:

A quadratic equation is in the form of :

`ax^(2) +bx+c=0`

And it is solved in the form of :

`x=\frac{-b+\sqrt{b^(-4ac) } }{2a}` and
`x=\frac{-b-\sqrt{b^(-4ac) } }{2a}`

Now the given equation is :

`x=\frac{-(-5)+-\sqrt{(-5)^(2) -4(7)(-2)} }{2(7)}`

We can see that here;

a = 7

b = -5

c = -2

So, the original equation must have been:

`7x^(2) -5x-2=0`