Verify Answer on Quadratic Formula

[Guest]

2x^2 - 5 = 4

2x^2 - 5 - 4 = 0

x = {-(-5) +/- SQRT [(-5)^2- 4(2)(-4)]} / [2(2)]

x = {5 +/- SQRT [25 + 32]} / 4

Answer: x = {5 +/- SQRT [57]} / 4

 

[stapel]

According to what you have posted, the equation is:

. . . . .2x² - 5 = 4

...which simplifies as:

. . . . .2x² = 9

Then the equation solves as:

. . . . .x² = 9/2 = 18/4

. . . . .x = ­± sqrt[18/4] = ± (3/2)sqrt[2]

Using the Quadratic Formula, one would have a = 2, b = 0, and c = -9, since there is no "x" term.

Eliz.