SOLUTION: You are adding 4 fractions. The denominators are: 3a, 24b, 7a, and 25b. What is the LCD?

Algebra ->  Numeric Fractions Calculators, Lesson and Practice -> SOLUTION: You are adding 4 fractions. The denominators are: 3a, 24b, 7a, and 25b. What is the LCD?      Log On


   



Question 148616: You are adding 4 fractions. The denominators are: 3a, 24b, 7a, and 25b. What is the LCD?
Found 2 solutions by stanbon, vleith:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
You are adding 4 fractions. The denominators are: 3a, 24b, 7a, and 25b. What is the LCD?
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It is the smallest monomial that each of these divides.
It is the least common multiply of all those denominators:
----------------You are adding 4 fractions. The denominators are: 3a, 24b, 7a, and 25b. What is the LCD?
It is 5^2*7*3*2^3ab = 4200ab
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Cheers,
Stan H

Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
You need to find the prime factors in each denominator value.
3a= 3 * a
24b = 2*2*2*3 * b
7a = 7 * a
25b = 5*5*b
Now look at each line above and find the lines that contain the 'most' factors of the same type.
3a has one 3 and one a. So we need 3 and a
24b has three 2's , one 3 and one b. We need the three 2's and the b. We already have one 3 from the previous entry.
7a has one 7 and one a. We already have one a, We need the one 7.
25b has two 5's and one b. We have one b already. We need both 5's since we don't have any of them yet.
So let's collect all the factors we 'kept' above.
3%2Aa+%2A+2%2A2%2A2+%2Ab++%2A7+%2A+5%2A5
So all we need to do now is multiply it all together to get
3%2A8%2A7%2A25+%2A+a%2Ab
4200%2Aab
4200ab