Hey!
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Solution:
~Isolate the 4
√x - 10 = 4
~Square both sides
√x - 10² = 4²
~Simplify
x - 10 = 16
~Add 16 to both sides
x - 10 + 10 = 16 + 10
~Simplify
x = 26
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Answer:

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Hope This Helped! Good Luck!