Question 377680
{{{0.7 = 90/(1+271e^(-0.122x))}}}
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{{{0.7(1+271e^(-0.122x))=90}}}
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{{{0.7+189.7e^(-0.122x)=90}}}
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{{{189.7e^(-0.122x)=89.3}}}
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{{{e^(-0.122x)=89.3/189.7}}}
Now take the natural log of both sides.
{{{-0.122x=ln(89.3/189.7)}}}
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{{{highlight(x=-(1/0.122)ln(89.3/189.7))}}}