



 
Hi Alicia, You want to start with the equation
manipulate it through a number of steps and end with an equation of the form
The changes you make at each step must maintain the equality of the two sides of the equation. The operations that will guarantee this are adding the same amount to each side and multiplying each side by the same amount. Here is one way to approach your problem. To eliminate the 18 you can multiply each side by 1/18. This gives On the left side 18 divided by 18 is 1 and on the right side 162/18 = 9 so the equation becomes
Finally adding 3 to each side yields
or
A second way to approach 18(C3) = 162 is to first expand the left side. This gives
or
Now add 54 to each side
or
At this stage multiply each side by 1/18 to get
I hope this helps,  


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