The answer to the question
C - (0.40c - 0.15) - (0.60c - 0.20)
I hope this helps :)
The answer would be 21/50. If you have numbers with a few zeros you can cross one of the top amd bottom until you reach the other numbers, if that makes sense. You can changd 420/1000 to 42/100. Then just keep dividing it by a numner that goes evenly into both the numerator and denominator.
B1 = 2
b2 = (b1)^2 + 1 = 2^2 + 1 = 5
b3 = (b2)^2 + 1 = 5^2 + 1 = 26
b4 = (b3)^2 + 1 = 26^2 + 1 = 676+1=<span>677</span>