Question 39580
1-) 8x^3+8x-6x --->8x^3+2x --->2x(4x^2+1)
    Anwser 2x(4x^2+1)
    Note: I think you might have copied the problem down wrong. Instead of 8x 
    it is 8x^2.
2-)24x^2-92x+80  --->4(6x^2-23x+20)--->4(3x-4)(2x-5)
   Anwser: 4(3x-4)(2x-5)
3-)6x^2+13x+6=0 --->(2x+3)(3x+2)=0
   2x+3=0 ====>  2x=-3 ==>x=-3/2
   3x+2=0 ====>  3x=-2 ==>x=-2/3
   Anwser x=-3/2 and x=-2/3
4-)2(a^2+9)=15a ---> 2a^2+18=15a --->2a^2-15a+18=0
   (2a-3)(a-6)=0
   2a-3=0 --->2a=3 --->a=3/2
   a-6=0  --->a=6
   Anwser a=3/2 and a=6