#b/((b+4)(b-4)) + 10/((b-9)(b+4))# its asking me to add these fractions by finding the LCD and I need help ?

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Answer 1 · 2017-02-21T17:07:17

See below.

#b/((b+4)(b-4) )+ 10/((b-9)(b+4) )#

Both denominator have the factors #(b+4)(b-4)(b-9)# so

multiplying and dividing both fractions for it we have

#1/((b+4)(b-4)(b-9))((b(b+4)(b-4)(b-9))/((b+4)(b-4) )+(10 (b+4)(b-4)(b-9))/((b-9)(b+4) ))=(b(b-9)+10(b+4))/((b+4)(b-4)(b-9))#

and finally

#b/((b+4)(b-4) )+ 10/((b-9)(b+4) )=(b^2+b+40)/((b+4)(b-4)(b-9))#