You would use distribution. So, in this case, it would be 10a - 50. You use -10 to multiply -a and 5, and you get 10a, and -50.
The y intercept is the point where the line passes through on the y-axis.for example on the graph that I showed we can see how the line passes through the 1 on the y-axis. This means 1 is our y-intercept. If you are still confused let me know lol
7/5h+3/5h-2=7
10/5h-2=7
2h=11
h=5.5
i’m pretty positive you would just subtract!