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secondary 4 | A Maths
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Please help me with this qn thanku :)
2lg10 + lg√(1 + x) + lg√(1 - x) + 2lg√(1 - x)
= lg√((1 + x)(1 - x))
lg10² + lg√(1 + x) + lg√(1 - x) + lg(√(1 - x))²
= lg√(1 + x) + lg√(1 - x)
lg100 + lg(1 - x) = 0
lg(100(1 - x)) = 0
100 - 100x = 1
99 = 100x
x = 99/100 = 0.99
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