Understand given logarithmic equation: Understand the given logarithmic equation.We have the equation log3x−4logx3=1+log931. We need to solve for x.
Use change of base formula: Use the change of base formula to rewrite 4logx3. Change of base formula: logab=log(c)alog(c)b4logx3=4×(log(x)log(3))
Simplify right side: Simplify the right side of the equation.We have (1)/(log93). Using the change of base formula again, we get:(1)/(log93)=log(3)/log(9)Since 9 is 32, log(9)=log(32)=2log(3), so:(1)/(log93)=log(3)/(2log(3))=1/2
Substitute simplified expressions: Substitute the simplified expressions back into the equation.Now we have log3x−4×(log(x)log(3))=1+21
Combine constants on right side: Combine the constants on the right side of the equation.1+21=23So, the equation becomes log3x−4⋅(log(x)log(3))=23
Convert to natural logarithm: Convert log3x to the natural logarithm using the change of base formula.log3x=log(3)log(x)The equation now is (log(3)log(x))−4⋅(log(x)log(3))=23
Multiply through to clear denominators: Multiply through by log(3)log(x) to clear the denominators.$log(x)⋅log(x) - 4 \cdot (\log(3) \cdot \log(3)) = \left(\frac{3}{2}\right) \cdot \log(3) \cdot \log(x)\)
Simplify the equation: Simplify the equation.(log(x))2−4⋅(log(3))2=23⋅log(3)⋅log(x)
Rearrange into quadratic form: Rearrange the equation into a quadratic form.Let's set A=log(x) and B=log(3), then we have:A2−23⋅B⋅A−4⋅B2=0
Solve quadratic equation for A: Solve the quadratic equation for A.This is a quadratic equation in the form of A2−C⋅A−D=0, where C=(23)⋅B and D=4⋅B2.We can use the quadratic formula to solve for A: A=2C±C2+4D
Calculate discriminant: Calculate the discriminant of the quadratic equation.The discriminant is C2+4D=(23⋅B)2+4⋅4⋅B2
Substitute B into discriminant: Substitute B=log(3) into the discriminant.Discriminant = (23⋅log(3))2+4⋅4⋅(log(3))2
Simplify the discriminant: Simplify the discriminant.Discriminant = (49)⋅(log(3))2+16⋅(log(3))2Discriminant = (49+16)⋅(log(3))2Discriminant = (49+464)⋅(log(3))2Discriminant = (\frac{\(73\)}{\(4\)}) \cdot (\log(\(3))^2
Solve for A using quadratic formula: Solve for A using the quadratic formula.A=2(23)∗B±(473)∗B2A=2(23)∗log(3)±(473)∗(log(3))2
Solve for x: Since A=log(x), we can solve for x.x=10Ax=10(23⋅log(3)±473⋅(log(3))2)/2
Realize mistake in previous step: Realize there is a mistake in the previous step.The base of the logarithm is 3, not 10. Therefore, we should use 3 as the base for exponentiation, not 10.x=3Ax=3(23⋅log(3)±473⋅(log(3))2)/2
More problems from Quotient property of logarithms