Question

ASAP MULTIPLE CHOICE:

Which equation could be solved using this application of the quadratic formula?

A. -2x2 − 8 = 10x − 3
B. 3x2 − 8x − 10 = 4
C. 3x2 + 8x − 10 = -8
D. -2x2 + 8x − 3 = 4

Answer 1

C.

Explanation:

Consider equation C:

3x^2 + 8x - 10 = -8

3x^2 + 8x - 2 = 0

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

Applying the quadratic formula:

x = [-b +/- √(b^2 - 4ac)] / 2a

x = [-8 +/- √(4(3)(-2)] / 2(3)

- which is the one in the question.

So it is equation C.

Answer 2

3x^2 +8x -10=-8

Explanation:

A quadratic equation is

ax^2 + bx +c=0

has a formula

-b ± sqrt( b^2 -4ac)

--------------------------

2a

We know a = 3 b = 8 and c = -2

3x^2 +8x -2=0

Subtract 8 from each side

3x^2 +8x -2 -8=0-8

3x^2 +8x -10=-8

That is choice C