Answer:
I do not fully understand this question so I will try to answer it the best I can.
25x^2-10x^2-13x=-7
15x^2-13x=-7
That is the question simplified. The part that you need to do from here is to figure out what x is. A way you can do that is by plugging in different solutions of what x could be until you find a solution that fits into the equation. I can't help that much but I hope that my solution helps.