ln 10 − ln(7 − 𝑥) = ln 𝑥
Solution
Sure, let's solve the equation step by step.
The equation is: ln 10 - ln(7 - x) = ln x
Step 1: Use the properties of logarithms to simplify the equation. The difference of two logarithms is the logarithm of the quotient, so we can rewrite the equation as:
ln(10/(7 - x)) = ln x
Step 2: If the natural logarithms of two numbers are equal, then the numbers themselves are equal. So we can write:
10/(7 - x) = x
Step 3: Solve this equation for x. First, multiply both sides by (7 - x) to get rid of the denominator:
10 = x*(7 - x)
Step 4: Distribute x on the right side:
10 = 7x - x^2
Step 5: Rearrange the equation to standard quadratic form:
x^2 - 7x + 10 = 0
Step 6: Factor the quadratic equation:
(x - 2)(x - 5) = 0
Step 7: Set each factor equal to zero and solve for x:
x - 2 = 0 => x = 2
x - 5 = 0 => x = 5
So the solutions to the equation are x = 2 and x = 5. However, we need to check these solutions in the original equation because logarithms are not defined for negative numbers or zero.
For x = 2, ln(10/(7 - 2)) = ln 2, which is true.
For x = 5, ln(10/(7 - 5)) = ln 5, which is also true.
So both x = 2 and x = 5 are solutions to the equation.
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