Answer:
13. x = 2.5, -2.5
14. x = 31, -31
15. x = 14.5717, -14.5717
Explanation:
13. log6[(4x²-1)(9)] = 3
36x² - 9 = 6³
36x² - 9 = 216
36x² = 225
x² = 225/36
x = +/- sqrt(225/36)
x = 2.5, -2.5
14. log7[(5x²-3)/2] = 4
(5x²-3)/2 = 7⁴
5x² - 3 = 4802
5x² = 4805
x² = 960
x = +/-sqrt(961)
x = 31, -31
15. log8[(3x²+3)/10] = 2
(3x²+3)/10 = 8²
3x² + 3 = 640
3x² = 637
x = +/- sqrt(637/3)
x = 14.5717, -14.5717