Question

Solve the equation. Write the solution set with the exact solutions. Also give approximate solutions to 4 decimal places if necessary. log (x2 - 2x) = log 15

Answer 1

x = -3, x = 5

Explanation:

log(x^2 - 2x) = log 15

e^(log(x^2 - 2x)) = e^(log(15))

x^2 - 2x = 15

x^2 - 2x - 15 = 0

x^2 - 5x + 3x - 15 = 0

x(x-5) + 3(x-5) = 0

(x+3)(x-5) = 0

(x+3) = 0 (x - 5) = 0

x = -3 x = 5