Isolve for x: ln(x^2-6x-16)= 0 . help me beacuse I do not have the idea to work it out.
3 answers
Solve for the value of x: ln(x^2-6x-16)=5. Please help me work it out because I do not have an idea in work it out.
(x^2-6x-15)=e^5
e^5 is approximately 148.41
so x^2-6x=148.41-15
x^2-6x = 133.41
x-6x = sqrt(133.41)
-5x = 11.55
x = 11.55/-5
x = 2.31
e^5 is approximately 148.41
so x^2-6x=148.41-15
x^2-6x = 133.41
x-6x = sqrt(133.41)
-5x = 11.55
x = 11.55/-5
x = 2.31
unfortunately Sunny made several errors,
Try to sub in x = 2.31, it does not work
form his/hers : (x^2-6x-16)=e^5 ---- Sunny had -15
x^2 - 6x = 148.413 + 16
complete the square by adding 9 to both sides
x^2 - 6x + 9 = 148.413+16+9 = 173.413
(x-3)^2 = 173.413
x-3 = ±√173.413 = ± 13.1686
x = 3 ± 13.1686
x = 16.1686 or x = -10.1686
both work when subbed into the original equation
Try to sub in x = 2.31, it does not work
form his/hers : (x^2-6x-16)=e^5 ---- Sunny had -15
x^2 - 6x = 148.413 + 16
complete the square by adding 9 to both sides
x^2 - 6x + 9 = 148.413+16+9 = 173.413
(x-3)^2 = 173.413
x-3 = ±√173.413 = ± 13.1686
x = 3 ± 13.1686
x = 16.1686 or x = -10.1686
both work when subbed into the original equation
5 answers