I got this on the calculator.
Answer:
Let first no. be x
Therefore,
2nd no. is x+1
Third no. is x+2
<em><u>SUM</u></em><em><u> </u></em><em><u>OF</u></em><em><u> </u></em><em><u>NO</u></em><em><u>.</u></em><em><u>'</u></em><em><u>s</u></em><em><u>=</u></em><em><u>x</u></em><em><u>+</u></em><em><u>x</u></em><em><u>+</u></em><em><u>1</u></em><em><u>+</u></em><em><u>x</u></em><em><u>+</u></em><em><u>2</u></em>
<em><u>S</u></em><em><u>=</u></em><em><u>3x</u></em><em><u>+</u></em><em><u>3</u></em>
<em><u>S</u></em><em><u>=</u></em><em><u>3</u></em><em><u>(</u></em><em><u>x</u></em><em><u>+</u></em><em><u>1</u></em><em><u>)</u></em>
Answer:
a) Not parallel to y-axis
b) Not parallel to y-axis
c) Parallel to y-axis
Step-by-step explanation:
The best way to check whether a line passing through two points is parlle to y-axis is by plotting them on graph.
The equation of line: 
a) The line joining the points (4,12) and ( 6,12) is not parallel to y-axis.
It is parallel to x-axis. Another two points that can lie on this line are : (5,12) and (
,12).
b) The line joining the points
is not parallel to y-axis.
Equation of line: 
Another points that could be lie on this line are (0.6,2) and (0.25,1.475)
c) The line joining the points
is parallel to y-axis because points have the same x-coordinate.
Another points that could be lie on this line are (0.8,2) and (0.8,2.1)
So you foil out the problem and get