If that says 10x^2 and -5x^2 then the answer is x= -2/5, x=4/3
First get all the variables on one side, so you have 15x^2-14x-8=0. Use the abc factoring method and get factors 6 and -20.Since a is not one, you must group the factors like this (15x^2-20x)(6x-8). Factor those out to get 5x(3x-4)+2(3x-4). Now you put those together to get (5x+2)(3x-4). Set them equal to zero and solve for x. 5x+2=0 ends up being x=-2/5 and 3x-4=0 ends up being x=4/3. Hope that helps!