SOLUTION: how would i do this? Combine the following fractions by addition or subtraction as directed 3a-4 over 5 + 7a-2 over 15 -4a+7 over 10

Algebra ->  Numeric Fractions Calculators, Lesson and Practice -> SOLUTION: how would i do this? Combine the following fractions by addition or subtraction as directed 3a-4 over 5 + 7a-2 over 15 -4a+7 over 10      Log On


   

Question 146872: how would i do this? Combine the following fractions by addition or subtraction as directed

3a-4 over 5 + 7a-2 over 15 -4a+7 over 10
Answer by mangopeeler07(462) About Me  (Show Source):
You can put this solution on YOUR website!
%283a-4%29%2F5+%287a-2%29%2F15-%284a%2B7%29%2F10. First you have to find a common denominator among all three fractions. Find the lowest number that is divisible by 5, 15, and 10. You should get 30. Divide 30 by each denominator. Whatever you got, multiply that number over itself by the fraction with the corresponding denominator. Your fractions should end up like this: %2818a-24%29%2F30+%2814a-4%29%2F30-%2812a%2B21%29%2F30. Then combine like terms over a single denominator; remember to distribute minus signs to the whole expression 12a%2B21! You should get %2818a-24%2B14a-4-12a-21%29%2F30. Then combine your like terms in the numerator. You should end up with %2820a-49%29%2F30. Since this cannot be reduced any further (without making decimals in the numerator), this is your final answer!