The points (5, -2 log8(t)) and (-4 log8(t), 5) lie on a line parallel to y = 7x + 2024.

Determine all possible values of t.

Solution:


The answer is t = 1/16.

Since the two given points lie on a line parallel to y = 7x + 2024, the slope of the line containing the two points must be equal to 7.   Use the formula for slope to set up the following equation:



Then 5 + 2 log8(t) = -28 log8(t) - 35
30 log8(t) = -40
log8(t) = -4/3
8 -4/3 = t


Another way to solve the problem is to substitute the coordinates of the two points into the general form of a line parallel to y = 7x + 2024.
The equation of the line is y = mx + 2024.
After substituting the two points, you obtain 2 equations with two variables:
-2 log8(t) = m (5) + 2024
5 = m ( -4 log8(t)) + 2024
Now solve the two equations simultaneously.



Correctly solved by:

1. Kamal Lohia Holy Angel School,
Hisar, Haryana, India
2. K. Sengupta Calcutta, India
3. Dr. Hari Kishan D.N. College,
Meerut, Uttar Pradesh, India
4. Davit Banana Istanbul, Turkey
5. Kelly Stubblefield Mobile, Alabama, USA