How do you solve the quadratic equation by completing the square: $2x² - 5x - 12 = 0$ ?

Question

3254 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2015-07-18T05:21:10

Solve $y = 2x^2 - 5x - 12 = 0$

x = 5/2 +- 7/2

$2(x^2 - (5x)/2 + 25/4) = 12 + 25/2$
$(x^2 - (5x)/2 + 25/4 = 6 + 25/4 = 49/4$
$(x - 5/2)^2 = 49/4$ --> $(x - 5/2) = +- 7/2$

$x = 5/2 +- 7/2$

How do you solve the quadratic equation by completing the square: 2x² - 5x - 12 = 02x² - 5x - 12 = 0?