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June 28th, 2017, 11:08 AM   #1
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Help with finding the Least Common Multiple(I think)

I'm working on some algebra, the Gauss-Jordan method by solving the systems of equations. In my matrix I have -4 in the first row second colum and -26 in the second row second column. The example wants to change -4 to 0 which I understand but I'm not sure how they go about it with the math. The example indicates:

-2R2 + 13R1 --> R1

How did they know to multiply -4 by 13 and -26 by -2?
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June 28th, 2017, 11:12 AM   #2
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Post the entire problem.
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June 28th, 2017, 11:22 AM   #3
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you're looking for LCM of 4 and 26. to find the the smallest number (not zero) that is a multiple of both 4 and 26, you should write each number in terms of a product of prime numbers:
4=2*2=2^2
26=2*13

then LCM is the product of multiplying the highest power of each prime number together
LCM(4,26)=LCM(2^2*13^0, 2^1*13^1)=2^2*13^1= 52 which means you have to multiply 4 by 13 and 26 by 2..
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June 28th, 2017, 11:23 AM   #4
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Use the Gauss Jordan method to transform the matrix:

3 -4 = 1
5 2 = 19
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June 28th, 2017, 01:15 PM   #5
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Thank you!
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