This is a solved problem and in this answer one of your experts wrote that :
In equation .1 y equals to c1a2-c2a1/a1b2-b2a1 but after substituting the values she wrote b2 equals to 1 and another b2 as -7. Sorry but I can't make it what your expert wanted to say can you resend or write something so that I can understand.
Dear student, The query provided by you appear to be confusing and I'm not getting what you are conveying because I am not getting your original question. Please post the question again so that you get meaningful assistance from our experts. Regards.