The principal value can also be obtained as follows:
Use the calculator on the home page here. Type in log(16,15) and press = or Enter
Add 8 to both sides: 8x ≤ -64
Divide both sides by 8 x ≤ -8
Have a look at http://www.purplemath.com/modules/stemleaf.htm
Press the 2nd button, then use acos (which is the same as cos-1)
There is no picture!
See https://web2.0calc.com/questions/ven-diagram-need-help-for-questions#r3 for instructions on how to upload a picture while the forum facility isn't working.
First find the prime factors of the two numbers:
924 = 2^2*3*7*11
126 = 2*3^2*7
For the HCF use the factors that are common to both: 2*3*7 = 42
For the LCM use the largest factors that appear in either set: 2^2*3^2*7*11 = 2772
You were right, because the result is the equation of a straight line!
Each time the x value goes up by 1 the y value decreases by 2 so the slope is -2/1 or just -2
Also when x = 0 the y value (the intercept) is 8
Hence y = -2x + 8
a = 0.6*b (60% = 0.6)
0.1*b = 30 (10% = 0.1)
Multiply the second equation by 10 to get b = 300
Put this in the first equation: a = 0.6*300 so a = 180
+33667 
