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Mistake in Line 2 : Was in the determining the values for a ,b,c
Mistake in Line 4 : Not taking the square roots of both sides.
Step-by-step explanation:

First Mistake : Line 2

Second Mistake : Line 4

Correct Solution :


Answer:
parallel lines
Step-by-step explanation:
parallel lines are lines that do not meet each other
Complete Question
The complete question is shown on the first uploaded
Answer:
is not a solution of the differential equation
is not a solution of the differential equation
is not a solution of the differential equation
Step-by-step explanation:
The differential equation given is 
Let consider the first equation to substitute



So


So

This means that
is not a solution of the differential equation
Let consider the second equation to substitute



So

So

This means that
is not a solution of the differential equation
Let consider the third equation to substitute



So

So
This means that
is not a solution of the differential equation