Mathematics

Question

What are the possible values for x in the equation 4x^2 = 64


(1) x=0        (2) x=4       (3) x=4,-4      (4) x=0,4,-4

2 Answer

  • 4x^2 = 64

    1)
    4(0^2) = 64
    4(0) = 64
    0 = 64
    Not True

    2)
    4(4^2) = 64
    4(16) = 64
    64 = 64
    True

    3)
    4(4^2) = 64
    4(16) = 64
    64 = 64
    4(-4^2) = 64
    4(16) = 64
    64 = 64
    True

    4)
    4(4^2) = 64
    4(16) = 64
    64 = 64
    4(-4^2) = 64
    4(16) = 64
    64 = 64
    4(0^2) = 64
    4(0) = 64
    0 = 64
    Not True

    Answer: (3)
  • [tex]4x^2 = 64\ \ /:4 \\ \\x^2=16 \\ \\ x^2-16=0 \\ \\x^2-4^2=0\\ \\ (x-4)(x+4)=0\\ \\x-4=0 \ \ or \ \ x+4=0 \\ \\ x=4 \ \ or \ \ x= -4 \\ \\ Answer : \ (3) [/tex]