How do you solve 8x^2-5=-4x?

1 Answer
Jun 15, 2018

=> x approx 0.57915

or

x approx -1.07915

Explanation:

8x^2-5=-4x

=> 8x^2-5+4x=0

=> 8x^2+4x -5=0 --------(1)

using quadratic equation formula:

=> x= (-b+- sqrt(b^2-4ac))/(2a)

Substitute the corresponding values of a,b, and c from (1)

=> x= (-4+- sqrt(4^2-4xx8xx(-5)))/(2xx8)

=> x= (-4+- sqrt(16+ 160))/(16)

=> x= (-4+- sqrt(176))/(16)

=> xapprox -4/16 +- 13.266499/16 ---truncating value of sqrt(176)

=>xapprox -1/4 +- 13.2665/16

=> x approx - 0.25 +- 0.82915

=> x approx - 0.25 + 0.82915 or x approx - 0.25 - 0.82915

=> x approx 0.57915

or

x approx -1.07915