Answer:





Step-by-step explanation:
Solving (a):
7x - 19 and 3x + 14 are interior angles.
So:

Collect like terms



7x - 19 and 5y - 2 are equal angles --- corresponding angles
So:

Make 5y the subject

5y = 7x -17
Make y the subject

Substitute 



Solving (b):
The triangle is right-angled.
So:

Collect Like Terms



Digits on the right are like units and digits on the left are like tenths
The graph that would easily allow us to see the increase or decrease of persons or individuals owning cellphone/s from 2000 to 2007, we could use bar graph. This bar graph represents the grouped data in rectangles and the number in y-axis would be shown to differ through the lengths of the bars.