RuralOregonDeputy RuralOregonDeputy
  • 01-05-2017
  • Mathematics
contestada

QUESTION FOR 50 POINTS
Solve this equation using an algebraic method: (x + 4)(x - 4) = 9
Choices are:
x=5
x=4 and x=-4
x=9
x=5 and x=-5

Respuesta :

irspow
irspow irspow
  • 01-05-2017
(x+4)(x-4)=9  expand left side by performing indicated multiplication...

x^2-16=9 add 16 to both sides

x^2=25  take the square root of both sides...

x=±5

x=-5 and 5

So the answer would be the bottom choice.
Answer Link
phillipino2002
phillipino2002 phillipino2002
  • 01-05-2017
the answer is 
x=5 and x=-5
Answer Link

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