0
Factoring and Multiples
This category should include questions about greatest common factors and lowest common multiples.
63,380 Questions
How do you find the least common denominatior of fractions?
It's the same process as finding the least common multiple.
Example: 7/30 + 13/42
Factor them.
2 x 3 x 5 = 30
2 x 3 x 7 = 42
Combine the factors, eliminating duplicates.
2 x 3 x 5 x 7 = 210, the LCM
Since 210 is the lowest common denominator, we can proceed to add them.
7/30 = 49/210
13/42 = 65/210
7/30 + 13/42 = 114/210 or 19/35 in lowest terms.
What are the prime factors and factors of 66?
Prime factors are 2, 3, 11
Other factors are combinations of the primes, i.e.
2 x 3 = 6
2 x 11 = 22
3 x 11 = 33
What is the answer for 30and 33 in the least common multiple?
The Least Common Multiple (LCM) of (30,33) is 330.
What is the least common multiple of 9 15 and 30?
The least common multiple of the numbers 30, 15 and 9 is 90.
1
Prime factors of 9 is 3 only. Prime factors of 35 are 7 and 5. Nothing in common so the common factor is 1.
The GCF is 1.
The GCF is 1.
How do you factor -x2 plus 5x plus 14?
Look for numbers that multiply to be 14, and add(or subtract) to be 5). In this case you want subtraction, since the x2 is negative. If you cannot figure out the factors, use the quadratic formula:
For ax2 + bx + c:
[-b +/- sqrt(b2 -4ac)] / (2a) = [-5 +/- sqrt(52 -4*(-1)*14)] / (-2) = 5/2 +/- sqrt(81)/2
= 5/2 +/- 9/2 --> 14/2 & -4/2 --> 7 & -2.
so this would factor to (-1)*(x - 7)*(x + 2) = (-x + 7)*(x + 2)
Note that 7*2=14 and 7x - 2x = 5x.
What are the factors of 279160?
1, 2, 4, 5, 7, 8, 10, 14, 20, 28, 35, 40, 56, 70, 140, 280, 997, 1994, 3988, 4985, 6979, 7976, 9970, 13958, 19940, 27916, 34895, 39880, 55832, 69790, 139580, 279160
What is the least common multiple of 5 8 12 and 90?
The Least Common Multiple (LCM) for 5 90 12 8 is 360.
