a) Not sure what that means. If you mean what is 'y' when x=0 then it is,

y=5(0)+7=7

b)Again I assume the same. You want to know for what 'x' do you get an output value of 37. Simple,

37=5x+7

How do you solve?

Subtract 7 from both sides,

30=5x

Now divide both sides by 5,

x=6.

All you need to do now is check, and it does work!

c) m represent the slope of the line. That is how steep it is. When the slope if big the line is getting closer and closer to a vertical line. When the slope is small, m=0 then it is a horizontal line. The 'b' terms shows the y-intercept that is the point on the y axis where the line crosses it. That means to find an equation of a line you need a slope and an intercept.