Search 75,879 tutors
FIND TUTORS
Ask a question
0 0

Multiply Rationals Expression and Functions

Multiply Rational Expression
 
  
                    (1)
 
  x^2-6x          x^2-6x-16
-----------   .   ---------------
x^2+2x-80      x^2-8x+12
 
                (2)
                                
  x^2+12x+20     x^2-x-56
----------------  . --------------
  x^2-13x+40     x^2+18x+90
 
                (3)
 
x^2+6x-55     x^3+216
------------- . --------------
  x^2+6x       x^2-9x+20
 
                (4)
 
2x^2+24x+22      x^2+3x-10
....................  .  .................
8x^2+104x+320   x^2+7x+6
 
                For the given functions f(x), find f(g).g(x)
 
          x^2-9x+20             x^2+6x-16
f(x) =  ............... ,g(x) = --------------
          x^2+x-2                x^2-25
 
                    
 
                        x^2+3x-28
f(x)=x+7,g(x)= ....................
                        x^2+14x+49
 
 
Tutors, please sign in to answer this question.

1 Answer

factor the terms of each fraction and simplify before you multiply
cross out each common factor that exists in a numerator and in a denominator
 
1)       (x)(x-6)        (x-8)(x+2)        (x)(x+2)
      __________  .  __________ =  _________
                                                     
      (x+10)(x-8)      (x-6)(x-2)        (x+10)(x-2)
 
 
 
2) I am assuming a typo in #2
 
       (x+10)(x+2)      (x-8)(x+7)       (x+2)(x+7)
      ___________  .  __________ =  __________
 
       (x-8)(x-5)         (x+8)(x+10)     (x-5)(x+8)
 
 
3)   (x+11)(x-5)       (x+6)(x^2-6x+36)       (x+11)(x^2-6x+36)
      __________  .   ________________ =   ________________
 
      (x)(x+6)            (x-5)(x-4)                    (x)(x-4)
 
 
4)   (2)(x+11)(x+1)       (x+5)(x-2)         (x+11)(x-2)
     ______________  .  __________  =  ___________
     
      (8)(x+8)(x+5)         (x+1)(x+6)       (4)(x+8)(x+6)
 
 
I assume you mean f(x)*g(x)
 
(x-5)(x-4)       (x+8)(x-2)       (x-4)(x+8)(x-2)
_________  .  _________  =  _____________
 
(x+2)(x-1)     (x-5)(x+5)       (x+2)(x-1)(x+5)
 
 
 
             (x+7)(x-4)
(x+7) .  __________  =  (x-4)
 
             (x+7)(x+7)