Some helppp me plzzz

Bring the fraction a/a-4 to a denominator of 16-a^2

Write 5(6x+4)-2(5x-2) in the form a(bx+c) where a,b and c integers and a> 1

Ur environment is very sensitive to the amount of ozone in the upper atmosphere. the level of ozone normally found is 4.04.0 parts/million (ppm). a researcher believes that the current ozone level is not at a normal level. the mean of 2525 samples is 4.44.4 ppm with a standard deviation of 0.80.8. assume the population is normally distributed. a level of significance of 0.020.02 will be used. make the decision to reject or fail to reject the null hypothesis. answer tables