Question

Find the discriminant: *
7x2 – 5 = 2x + 9x2

Answer 1

-36

Explanation:

You have to rearrange the quadratic into an equation where one side is zero.

This example works by subtracting 7x^2 from both sides leaving

-5 = 9x^2 - 7x^2 + 2x

-5 = 2x^2 + 2x

Now add 5 to both sides

-5 + 5 = 2x^2 + 2x + 5

0 = 2x^2 + 2x + 5

Now the equation you gave is in the form of a quadratic. The discriminate is found from

a = 2

b = 2

c = 5

b^2 - 4ac is the discriminate

2^2 - 4(2)(5)

4 - 40

Discrimate = 4 - 40 = - 36