Put the decimal over 100 and get rid of the decimal
        
             
        
        
        
-24a²- 6a +9 = - 3(8a² +6a - 9)
8a² +6a - 9 =0
x=(-b +/-√(b² - 4ac))/2a
x = (-6 +/-√(36+4*8*9)  /(2*8) = (-6 +/-√(324)  /16 =  (-6 +/-18)/16
x1 =  (-6 +18)/16 = 0.75
x2 =  (-6 -18)/16 = - 1.5
-24a²- 6a +9 = - 3(8a² +6a - 9) = -3(a - 0.75)(a + 1.5)