Verified Answer :

  1. Subtract 64 from each side of the equation

    -36=-9x^2

    2. Separate -9 from x^2 by dividing -9 from each side. The negatives will cancel leaving a positive on the left.

    4=x^2

    3. Last, take the square root of each side in order to get rid of the exponent.

    2=x

    4. Quick Check

    28=64-9(2)^2
    28=64-9(4)
    28=64-36
    28=28

\(28=64-9{ x }^{ 2 }\\ \\ 9{ x }^{ 2 }=64-28\\ \\ 9{ x }^{ 2 }=36\)

\(\\ \\ \frac { 1 }{ 9 } \cdot 9{ x }^{ 2 }=\frac { 1 }{ 9 } \cdot 36\\ \\ { x }^{ 2 }=4\\ \\ x=\pm \sqrt { 4 }\)

\(\\ \\ \therefore \quad x=\pm 2\)

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