Use point slope form to answer this
Y = x - 10
8(x+3)
In this form, it is fully factored. All you need is a GCF, which is 8.
Hope this helps!
The answer to your question is <-8 :)
Since grades are out of 100, you can just subtract 75 from 90 which is 15. the percent of increase in the student's grade is 15%