 Quandaries and Queries Secondary Student Hi, I have a career link question from gr.12 advanced functions and intro. calculus. The equations is: R(t) = 5(t4 - 4t3 + 19/4 t2 - 3/2 t) The question is to apply the factor theorem and quadratic formula to determine the times it crosses the t axis. The only method i know of for using the factor theorem is when the last number does not have a variable beside it so i'm not sure how you would even use the factor theorem for this? We haven't dealt with any that have 0 as the last number with no variable so i'm a little confused! please help! Thank you LisaMarie Hi LisaMarie, What you need to see is that t is a common factor in the expression for R(t). You can take it out as a common factor to get R(t) = 5t(t3 - 4 t2 + 19/4 t -  3/2) To use the factor theorem you want all the coefficients to be integers so put the expression inside the parentheses over a common denominator of 4 to get R(t) = 5/4 t(4 t3 - 16 t2 + 19 t -  6) Now apply the factor theorem. Penny Go to Math Central