Dr bell donated 2(3x+60) dollars to the salvation army, 5x dollars to the church and $100 to a sport shop. if he donated a total of $550, how much did he donated to salvation army?

He donated $285 to the salvation army.
The first thing to do is solve for "x". The equation would be {2(3x+60)}+5x+100=550. 
Then, you would multiply 2 with 3x and 60. Your new equation would be 5x+120+5x+100=550. 
Next, you would combine like terms. This means to combine the terms that are similar. In this case, it would be the whole numbers and the numbers with the variable. Your new equation would be 10x+220=550. 
After that, you subtract 220 on both sides of the equal sign. This makes the equation 10x=330. 
Then, you divide ten on both sides of the equal sign, giving you x=33.
The second things to is replace the x with 33. The amount for the salvation army is 5x+120. Replacing 33 with x, your final equation will be 165+120=$285.

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