I am taking one part of question

a) y= 3x+5 , y=2x+4

Solving two equations

Put value of y from second equation in first

2x+4=3x+5
3x-2x=4-5
x=-1

Put this value in any of the equation

y=3x+5
y=-3+5=2

so these two intersect at ( -1 , 2)

I have drawn graphs for both of these  , just drawn these on one sheet of graph and see these intersect at ( -1 , 2)

y=3x+5

y=2x+4

Part b) 

y= -0.5x+2, y=0.5x-3

Graphs for both of these have been drawn just see points at which the intersect after drawing them on common sheet of graph 

y= -0.5x+2

y=0.5x-3