Question 283328
First we need to simplify the equation:
4*x*(x-9)-5*x*(x-8)=-5
*[invoke explain_simplification "4*x*(x-9)-5*x*(x-8)=-5" ]

Notice that this turns it into the quadratic {{{-x^2 + 4*x + 5 = 0}}}, which you can solve as any standard quadratic in the form of {{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} and bob's your uncle!