Please Explain

Find the t-value(s) for each of the following cases. Round your answers to 3 decimal places. Enter negative values as negative number. a. Upper tail area of .10 with 15 degrees of freedom is :J . b. Lower tail area of .05 with 50 degrees of freedom is :l . c. Upper tail area of .01 with 30 degrees of freedom is [j . d. Where 98% of the area falls between these two t-values with 20 degrees of freedom. (:JICJ) e. Where 95% of the area falls between these two t-values with 45 degrees of freedom. (:JICJ)