Since x is on the right side of the equation, switch the sides so it is on the left side of the equation.log3(x2+18)=5log3x2+18=5Rewrite log3(x2+18)=5log3x2+18=5 in exponential form using the definition of a logarithm. If x and b are positive real numbers and b≠1, then logb(x)=y is equivalent to b^y=x.3^5=x^2+18Raise 3 to the power of 5 to get 243.243=x^2+18Since x is on the right side of the equation, switch the sides so it is on the left side of the equation.x^2+18=35Raise 3 to the power of 5 to get 243.x^2+18=243Move all terms not containing x to the right side of the equationSince 18 does not contain the variable to solve for, move it to the right side of the equation by subtracting 18 from both sides.x^2=−18+243Add −18 and 243to get 225.x^2=225

Take the square root of both sides of the equation to eliminate the exponent on the left side.x=±√225xThe complete solution is the result of both the positive and negative portions of the solution.

Rewrite 225 as 152.x=±152Pull terms out from under the radical, assuming positive real numbers.x=±15