How do you solve the quadratic with complex numbers given #-5x^2+12x-8=0#? Precalculus Linear and Quadratic Functions The Quadratic Formula 1 Answer sankarankalyanam Jan 30, 2018 #x = 1.2 - 0.1 sqrt26 color(red)i, 1.2 + 0.1 sqrt26 color(red)i# Explanation: #-5x^2 + 12x - 8 = 0# #x = (-b +- sqrt(b^2 - (4 a c))) / (2 * a)# #a = -5, b = 12, c = -8# #x = (-12 +- sqrt(12^2 - (4 * -5 * - 8))) / (2 * -5)# #x = (-12 +- sqrt(144 - 160)) / (-10)# #x = 1.2+- 0.1 sqrt(-26)# #x = 1.2 +- 0.1 sqrt26 color(red)i# Answer link Related questions What are common mistakes students make when using the quadratic formula? What do the variables in the quadratic formula mean? What are the possible outcomes when using the quadratic formula? How do I use the quadratic formula to solve #f(x) = x^2 + 3x - 2#? How do I use the quadratic formula to solve #f(x) = 4x^2 + 12x + 9#? How do I use the quadratic formula to solve #f(x) = x^2 + 3x - 7#? What is the discriminant of a quadratic function? Can the quadratic formula be used to solve a linear equation? How do I use the quadratic formula to solve #3x^2 - 6 = 4x#? How do I use the quadratic formula to solve #4x^2+x-1=0#? See all questions in The Quadratic Formula Impact of this question 1443 views around the world You can reuse this answer Creative Commons License