Question 2

Solve the following linear equation:

Select and check your answer...

A. +3
B. -3
C. -2
D. 2

To solve the linear equation, add -3 to both sides of the equation to remove +3. The equation becomes:
                            r +3 -3 = 9 -2r -3

Now, on the Left Hand Side (LHS) of the equation, +3 and -3 cancels off.  We are left with :  
                                r = 9 -2r -3 

Keeping the objective in mind, r = ?, we need to remove -2r on the Right Hand Side (RHS) of the equation. Hence, adding +2r to both sides:
 
                            r +2r = 9 -2r +2r -3

Now, on the RHS, -2r and +2r cancels off.  We are left with:
  
                                r +2r = 9 -3 

Now, we can simplifying the terms on the LHS by adding r and 2r. This gives 3r.
 
                      3r = 9 -3

Similarly, simplifying the terms in the RHS adding 9 and -3. This gives 6  

                       3r = 6  

Realize that to get r = ?, we need to remove 3 from 3r. To do so, we can divide both sides by 3 as shown in the picture.



Now, on the LHS, the we 3 divides by 3 cancels off.
So, we are left with r = 6/3.

Now, on the RHS, 6/3 gives 2. Finally, we have r = 2.

So, the answer is D.