Remember order of operation.
-3xy =45		Think! How did x become y?
Negative integers must follow rules when multiplying.		Change the value of one variable and you change both if the equation stays true.

  

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All those letters getting you down? You thought math was supposed to be numbers. Go
 ahead and bang your feet, but help is on the way.

The number of variables changes the ease of solving.   A problem with only one variable
 ( unknown replaced by a letter) is the easiest. The goal is to get to x =  or even    =x

Try this on your own, written on paper. If you need help, click
the black rectangles.

 

First in the order of operations we do	parenthesis	since that includes a variable we	multiply each variable or number
we get the answer	2x-10	then the problem looks like	3x +2x-10=50
Combine like terms	5x -10 =50	get the numbers on one side	Add 10 to each side and get 5x=60
almost there, now get the X alone	divide both sides by 5	the final answer is	x = 12

 

                    Try this one.   Do it on your paper before you choose the answer.

                    4x + 3( x +2) =76

                    a. 16

                    b. 10

                    c. 7

         

Input- output is about doing the same thing to x  to get y. Since x always changes, y changes.

 

                                                             

Here is an easy one.

input ( x)	7	9	11	Easy you multiply times 3.
output  (y)	21	27	33	3x = y