Advanced Functions (MHF4U) · Exponential and Logarithmic Functions

Solving logarithmic equations

Solve logarithmic equations, including ones that combine into a quadratic and need an extraneous root check. Unlimited questions, five difficulty levels, and a full worked solution every time — free.

Practice this skill Curriculum: MHF4U-EL3.3

Try one

Solve for x.

log3(x - 4) = 4

Answer: 85

See one solved, step by step

Solve for x.

log3(x) + log3(3) = 5
📘 Worked solution
1log3(x) + log3(3) = 5Start with the equation.
2log3(3x) = 5Product law: combine the two logs into one.
33x = 35 = 243Rewrite in exponential form.
4x = 2433 = 81Divide both sides by 3 to isolate x.

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