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Answer Key 8.7

  1. LCD=2(x)3x(2x)−x−2=06x2−x−2=0(3x−2)(2x+1)=0x=23,−12
  2. LCD=x+1(x+1)(x+1)=−4x2+2x+1=−4−4−4x2+2x−3=0(x−1)(x+3)=0x=1,−3
  3. LCD=x−4x(x−4)+20=5x−2(x−4)x2−4x+20=5x−2x+8−3x−8−3x−8x2−7x+12=0(x−4)(x−3)=0x=3,4
  4. LCD=x−1x2+6+x−2=−2x(x−1)x2+x+4=−2x2−2x−2x2+2x−2x2+2x−x2+3x+4=0x2−3x−4=0(x−4)(x+1)=0x=4,1
  5. LCD=x−3x(x−3)+6=2xx2−3x+6=2x−2x−2xx2−5x+6=0(x−3)(x−2)=0x=2,3
  6. LCD=(x−1)(3−x)(x−4)(3−x)=−12(x−1)+(x−1)(3−x)−x2+7x−12=−12x−12−x2+4x−3+x2−16x+15−12x+12+x2−4x+3−9x+3=03=9xx=39 or13
  7. LCD=(2m−5)(3m+1)(2)3m(3m+1)(2)−7(2m−5)(2)=3(2m−5)(3m+1)18m2+6m−28m+70=18m2−39m−15−18m2+39m+15−18m2+39m+1517m+85=0−85−8517m17=−8517m=−5
  8. LCD=(1−x)(3−x)(4−x)(3−x)=12(1−x)12−7x+x2=12−12x−12+12x−12+12xx2+5x=0x(x+5)=0x=0,−5
  9. LCD=2(y−3)(y−4)7(2)(y−4)−1(y−3)(y−4)=(y−2)(2)(y−3)14y−56−y2+7y−12=2y2−10y+12−0y2+21y−68=2y2−10y+12−2y2+10y−12−2y2+10y−12−3y2+31y−80=03y2−31y+80=0(y−5)(3y−16)=0y=5,163
  10. LCD=(x+2)(x−2)1(x−2)+1(x+2)=3x+8x−2+x+2=3x+8−2x−2x0=x+8−8−8x=−8
  11. LCD=(x+1)(x−1)(6)(x+1)(x+1)(6)−(x−1)(x−1)(6)=5(x+1)(x−1)6(x2+2x+1)−6(x2−2x+1)=5(x2−1)6x2+12x+6−6x2+12x−6=5x2−524x=5x2−5−24x−24x0=5x2−24x−50=(5x+1)(x−5)x=5,−15
  12. LCD=(x+3)(x−2)(x−2)(x−2)−1(x+3)=1x2−4x+4−x−3=1−1−1x2−5x=0x(x−5)=0x=0,5
  13. LCD=(x−1)(x+1)x(x+1)−2(x−1)=4x2x2+x−2x+2=4x2−x2+x−2−x2+x−20=3x2+x−20=(3x−2)(x+1)0=23,−1
  14. LCD=(x+2)(x−4)2x(x−4)+2(x+2)=3x2x2−8x+2x+4=3x−3x−3x2x2−9x+4=0(2x−1)(x−4)=0x=12,4
  15. LCD=(x+1)(x+5)2x(x+5)−3(x+1)=−8x22x2+10x−3x−3=−8x2+8x2+8x210x2+7x−3=0(10x−3)(x+1)=0x=310,−1

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Intermediate Algebra (Convert to MathJax) Copyright © 2020 by Terrance Berg is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

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