The answer is: " 100 " .
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Explanation:
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10x + 10(x + 1) = 210 ; Solve for "10x" ;
10x + 10x + 10 = 210 ;
20x + 10 = 210 ;
Subtract "10" from each side of the equation;
20x + 10 - 10 = 210 - 10 ;
to get: 20x = 200 ;
Divide EACH SIDE of the equation by "20" ;
20x / 20 = 200 / 20 ;
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to get: x = 10 ;
Now; solve for "10x" ;
10x = 10 * x = 10 * 10 = 100.
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The answer is: " 100 " .
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