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I don't know why the answer can be 3 OR 7. Please help me.

I don't know why the answer can be 3 OR 7. Please help me.-example-1

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Answer:

see explanation

Explanation:

Calculate the distance (d) using the distance formula

d = √ (x₂ - x₁ )² + (y₂ - y₁ )²

with (x₁, y₁ ) = (3, 5) and (x₂, y₂ ) = (1, a)

d =
√((1-3)^2+(a-5)^2)

=
√((-2)^2+(a-5)^2)

=
√(4+(a-5)^2)

Equating d to
√(8), gives


√(4+(a-5)^2) =
√(8)

Squaring both sides

4 + (a - 5)² = 8 ( subtract 4 from both sides )

(a - 5)² = 4 ( take the square root of both sides )

a - 5 = ±
√(4) = ± 2 ( add 5 to both sides )

a = 5 ± 2, that is

a = 5 - 2 = 3 OR a = 5 + 2 = 7

User Andy Lindeman
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