Question
Solve the equation
x=421
Alternative Form
x=5.25
Evaluate
log2(x−3)−log2(x×1)=log2(3)−log2(7)
Find the domain
More Steps

Evaluate
{x−3>0x×1>0
Calculate
More Steps

Evaluate
x−3>0
Move the constant to the right side
x>0+3
Removing 0 doesn't change the value,so remove it from the expression
x>3
{x>3x×1>0
Any expression multiplied by 1 remains the same
{x>3x>0
Find the intersection
x>3
log2(x−3)−log2(x×1)=log2(3)−log2(7),x>3
Simplify
More Steps

Evaluate
log2(x−3)−log2(x×1)
Any expression multiplied by 1 remains the same
log2(x−3)−log2(x)
Use logax−logay=logayx to transform the expression
log2(xx−3)
log2(xx−3)=log2(3)−log2(7)
Use the logarithm product rule
log2(xx−3)=log2(73)
Evaluate the logarithm
xx−3=73
Cross multiply
(x−3)×7=x×3
Simplify the equation
7(x−3)=x×3
Simplify the equation
7(x−3)=3x
Expand the expression
More Steps

Evaluate
7(x−3)
Apply the distributive property
7x−7×3
Multiply the numbers
7x−21
7x−21=3x
Move the variable to the left side
7x−21−3x=0
Subtract the terms
More Steps

Evaluate
7x−3x
Collect like terms by calculating the sum or difference of their coefficients
(7−3)x
Subtract the numbers
4x
4x−21=0
Move the constant to the right side
4x=0+21
Removing 0 doesn't change the value,so remove it from the expression
4x=21
Divide both sides
44x=421
Divide the numbers
x=421
Check if the solution is in the defined range
x=421,x>3
Solution
x=421
Alternative Form
x=5.25
Show Solution
