Question
Solve the equation
x1=10,x2=10000
Evaluate
(log10(x))2−3log10(x)=log10(x2)−4
Find the domain
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Evaluate
{x>0x2>0
Calculate
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Evaluate
x2>0
Since the left-hand side is always positive or 0,and the right-hand side is always 0,the statement is true for any value of x,except when x2=0
x2=0
The only way a power can be 0 is when the base equals 0
x=0
Exclude the impossible values of x
x=0
{x>0x=0
Find the intersection
x>0
(log10(x))2−3log10(x)=log10(x2)−4,x>0
Move the expression to the left side
(log10(x))2−3log10(x)−(log10(x2)−4)=0
Subtract the terms
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Evaluate
(log10(x))2−3log10(x)−(log10(x2)−4)
If a negative sign or a subtraction symbol appears outside parentheses, remove the parentheses and change the sign of every term within the parentheses
(log10(x))2−3log10(x)−log10(x2)+4
Subtract the terms
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Evaluate
−3log10(x)−log10(x2)
Use the logarithm base change rule
−log10(x3)−log10(x2)
Rewrite the expression
−(log10(x3)+log10(x2))
Use logax+logay=logaxy to transform the expression
−log10(x3×x2)
Multiply the terms
−log10(x5)
(log10(x))2−log10(x5)+4
(log10(x))2−log10(x5)+4=0
Use logabn=nlogab to simplify the expression
(log10(x))2−5log10(x)+4=0
Factor the expression
(log10(x)−4)(log10(x)−1)=0
Separate the equation into 2 possible cases
log10(x)−4=0log10(x)−1=0
Solve the equation
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Evaluate
log10(x)−4=0
Move the constant to the right-hand side and change its sign
log10(x)=0+4
Removing 0 doesn't change the value,so remove it from the expression
log10(x)=4
Convert the logarithm into exponential form using the fact that logax=b is equal to x=ab
x=104
Evaluate the power
x=10000
x=10000log10(x)−1=0
Solve the equation
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Evaluate
log10(x)−1=0
Move the constant to the right-hand side and change its sign
log10(x)=0+1
Removing 0 doesn't change the value,so remove it from the expression
log10(x)=1
Convert the logarithm into exponential form using the fact that logax=b is equal to x=ab
x=101
Evaluate the power
x=10
x=10000x=10
Check if the solution is in the defined range
x=10000x=10,x>0
Find the intersection of the solution and the defined range
x=10000x=10
Solution
x1=10,x2=10000
Show Solution
