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Adding fractions by finding the LCD?

I can't seem to get past this problem...

  2x   +     5   

  3x         x-8


For the answer I keep getting something like:  17x-13



Thanks for your help!


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Shannon M. | Biology Major Specializing in Science and MathBiology Major Specializing in Science an...
4.9 4.9 (81 lesson ratings) (81)

Once you find the LCD, which you have done correctly, you have to multiply the numerator and denominator of each by the same factor:

 2x  (x-8)  +    5  (3x)

 3x   (x-8)      x-8 (3x)


2x2 - 16x  + 8x   =  2x2 -8x    =   (x)(2x -4)    =  2x-4 

(3x)(x-8)               3x2 - 24x       (x)(3x-24)        3x-24


The end answer is not right on this. Sorry multiplication error. Should be 2x-1/3x-24

Asok B. | Ph. D in Biochemistry, willing to teach Chemistry, Biochemistry, MathPh. D in Biochemistry, willing to teach ...
4.7 4.7 (18 lesson ratings) (18)

 your answer = {2x(x-8) + 15x}/3x(x-8) 

= (2x2-16x+15x)/3x(x-8)

= (2x2-x)/3x(x-8)