How do you solve #x^2-5x-8=0#? Algebra Quadratic Equations and Functions Quadratic Functions and Their Graphs 1 Answer Binayaka C. May 10, 2016 The roots are #6.275, -1.275# Explanation: This is a quadratic equation of form #ax^2+bx+c# where #a=1;b=-5;c=-8 ; b^2-4ac=25+32=57(+)#ive. So roots are real. #x= -b/(2a) +- sqrt (b^2-4ac)/(2a)= 2.5 +- sqrt57/2 = 6.275, -1.275# [Ans] Answer link Related questions What are the important features of the graphs of quadratic functions? What do quadratic function graphs look like? How do you find the x intercepts of a quadratic function? How do you determine the vertex and direction when given a quadratic function? How do you determine the range of a quadratic function? What is the domain of quadratic functions? How do you find the maximum or minimum of quadratic functions? How do you graph #y=x^2-2x+3#? How do you know if #y=16-4x^2# opens up or down? How do you find the x-coordinate of the vertex for the graph #4x^2+16x+12=0#? See all questions in Quadratic Functions and Their Graphs Impact of this question 3630 views around the world You can reuse this answer Creative Commons License