Asksia AI LOGO

Sia

天翔's Question
Math
Posted 6 months ago

7 Solve each of the following equations.
a log3x+log35=log3(2x+3)\log _{3} x+\log _{3} 5=\log _{3}(2 x+3)
b log9x+log910=32\log _{9} x+\log _{9} 10=\frac{3}{2}
c log4xlog4(x1)=log43+12\log _{4} x-\log _{4}(x-1)=\log _{4} 3+\frac{1}{2}
d log55xlog5(x+2)=log5(x+6)log5x\log _{5} 5 x-\log _{5}(x+2)=\log _{5}(x+6)-\log _{5} x
e 2log6x=log6(2x5)+log652 \log _{6} x=\log _{6}(2 x-5)+\log _{6} 5
f log74x=log71x6+1\log _{7} 4 x=\log _{7} \frac{1}{x-6}+1
8 Solve each pair of simultaneous equations.
a logxy=2\log _{x} y=2 xy=27x y=27
b log5x2log5y=log52\log _{5} x-2 \log _{5} y=\log _{5} 2 x+y2=12x+y^{2}=12
c log2x=32log2y\log _{2} x=3-2 \log _{2} y
d logyx=32\log _{y} x=\frac{3}{2}
logy32=52\log _{y} 32=-\frac{5}{2}
x13+3y12=20x^{\frac{1}{3}}+3 y^{\frac{1}{2}}=20
e logax+loga3=12logay\log _{a} x+\log _{a} 3=\frac{1}{2} \log _{a} y
f log10y+2log10x=3\log _{10} y+2 \log _{10} x=3 3x+y=203 x+y=20
log2ylog2x=3\log _{2} y-\log _{2} x=3
Sign in to unlock the answer
Answer from Sia
Posted 6 months ago
Solution by Steps
step 1
Simplify the given equation using the properties of logarithms: log3x+log35=log3(2x+3) \log_{3} x + \log_{3} 5 = \log_{3} (2x + 3)
step 2
Combine the logarithms on the left side: log3(5x)=log3(2x+3) \log_{3} (5x) = \log_{3} (2x + 3)
step 3
Since the bases and the arguments are equal, set the arguments equal to each other: 5x=2x+3 5x = 2x + 3
step 4
Solve for x x by isolating it on one side: 5x2x=3    3x=3    x=1 5x - 2x = 3 \implies 3x = 3 \implies x = 1


 Question 7b
step 1
Simplify the given equation using the properties of logarithms: log9x+log910=32 \log_{9} x + \log_{9} 10 = \frac{3}{2}
step 2
Combine the logarithms on the left side: log9(10x)=32 \log_{9} (10x) = \frac{3}{2}
step 3
Rewrite the equation in exponential form: 10x=93/2 10x = 9^{3/2}
step 4
Simplify the right side: 93/2=(32)3/2=33=27 9^{3/2} = (3^2)^{3/2} = 3^3 = 27
step 5
Solve for x x by isolating it on one side: 10x=27    x=2710=2.7 10x = 27 \implies x = \frac{27}{10} = 2.7


 Question 7c
step 1
Simplify the given equation using the properties of logarithms: log4xlog4(x1)=log43+12 \log_{4} x - \log_{4} (x - 1) = \log_{4} 3 + \frac{1}{2}
step 2
Combine the logarithms on the left side: log4(xx1)=log4(34) \log_{4} \left( \frac{x}{x - 1} \right) = \log_{4} (3 \cdot \sqrt{4})
step 3
Simplify the right side: log4(32)=log46 \log_{4} (3 \cdot 2) = \log_{4} 6
step 4
Since the bases and the arguments are equal, set the arguments equal to each other: xx1=6 \frac{x}{x - 1} = 6
step 5
Solve for x x by isolating it on one side: x=6(x1)    x=6x6    5x=6    x=65=1.2 x = 6(x - 1) \implies x = 6x - 6 \implies 5x = 6 \implies x = \frac{6}{5} = 1.2


 Question 7d
step 1
Simplify the given equation using the properties of logarithms: log55xlog5(x+2)=log5(x+6)log5x \log_{5} 5x - \log_{5} (x + 2) = \log_{5} (x + 6) - \log_{5} x
step 2
Combine the logarithms on both sides: log5(5xx+2)=log5(x+6x) \log_{5} \left( \frac{5x}{x + 2} \right) = \log_{5} \left( \frac{x + 6}{x} \right)
step 3
Since the bases and the arguments are equal, set the arguments equal to each other: 5xx+2=x+6x \frac{5x}{x + 2} = \frac{x + 6}{x}
step 4
Cross-multiply to solve for x x : 5x2=(x+2)(x+6)    5x2=x2+8x+12 5x^2 = (x + 2)(x + 6) \implies 5x^2 = x^2 + 8x + 12
step 5
Simplify and solve the quadratic equation: 4x28x12=0    x22x3=0    (x3)(x+1)=0 4x^2 - 8x - 12 = 0 \implies x^2 - 2x - 3 = 0 \implies (x - 3)(x + 1) = 0
step 6
Solve for x x : x=3 x = 3 or x=1 x = -1 (since x x must be positive, x=3 x = 3 )


 Question 7e
step 1
Simplify the given equation using the properties of logarithms: 2log6x=log6(2x5)+log65 2 \log_{6} x = \log_{6} (2x - 5) + \log_{6} 5
step 2
Combine the logarithms on the right side: 2log6x=log6(5(2x5)) 2 \log_{6} x = \log_{6} (5(2x - 5))
step 3
Simplify the right side: 2log6x=log6(10x25) 2 \log_{6} x = \log_{6} (10x - 25)
step 4
Rewrite the left side: log6(x2)=log6(10x25) \log_{6} (x^2) = \log_{6} (10x - 25)
step 5
Since the bases and the arguments are equal, set the arguments equal to each other: x2=10x25 x^2 = 10x - 25
step 6
Solve the quadratic equation: x210x+25=0    (x5)2=0    x=5 x^2 - 10x + 25 = 0 \implies (x - 5)^2 = 0 \implies x = 5


 Question 7f
step 1
Simplify the given equation using the properties of logarithms: log74x=log7(1x6)+1 \log_{7} 4x = \log_{7} \left( \frac{1}{x - 6} \right) + 1
step 2
Rewrite the right side: log74x=log7(1x6)+log77 \log_{7} 4x = \log_{7} \left( \frac{1}{x - 6} \right) + \log_{7} 7
step 3
Combine the logarithms on the right side: log74x=log7(7x6) \log_{7} 4x = \log_{7} \left( \frac{7}{x - 6} \right)
step 4
Since the bases and the arguments are equal, set the arguments equal to each other: 4x=7x6 4x = \frac{7}{x - 6}
step 5
Cross-multiply to solve for x x : 4x(x6)=7    4x224x7=0 4x(x - 6) = 7 \implies 4x^2 - 24x - 7 = 0
step 6
Solve the quadratic equation using the quadratic formula: x=24±242+44724=24±7848=24±288 x = \frac{24 \pm \sqrt{24^2 + 4 \cdot 4 \cdot 7}}{2 \cdot 4} = \frac{24 \pm \sqrt{784}}{8} = \frac{24 \pm 28}{8}
step 7
Simplify the solutions: x=528=6.5 x = \frac{52}{8} = 6.5 or x=48=0.5 x = \frac{-4}{8} = -0.5 (since x x must be positive, x=6.5 x = 6.5 )
Answer
7a: x=1 x = 1
7b: x=2.7 x = 2.7
7c: x=1.2 x = 1.2
7d: x=3 x = 3
7e: x=5 x = 5
7f: x=6.5 x = 6.5
Key Concept
Logarithmic Equations
Explanation
To solve logarithmic equations, use properties of logarithms to combine or simplify terms, then convert to exponential form if necessary and solve for the variable.

Not the question you are looking for? Ask here!

Enter question by text

Enter question by image

Unlock Smarter Learning with AskSia Super!

Join Super, our all-in-one AI solution that can greatly improve your learning efficiency.

30% higher accuracy than GPT-4o
Entire learning journey support
The most student-friendly features
Study Other Question