As a town gets smaller, the population of its high school decreases by 6% each year, teh senior class has 250 students now. in how many years will it have about 100 students

An equation to solve for the time when the high school will have exactly 100 students is (1-.06)^x = (250/100).  
That simplifies to 94^x = .4.  
We can then take the log of both sides to isolate the x variable from the exponent. Here's with natural log.  
x*ln(.94)=ln(.4)
 x = ln(.4)/ln(.94)  
Solving this gives x ~= 14.80. So in about 15 years, the high school will have 100 students.

Number 5 is 50 degreesnumber 6 is 45 degreesnumber 7 is 60 degreesnumber 8 is 45 degrees

12+3b -1=-5-b -12-1+5=-b-3b -8=-4b