step1) divide 1st term by the 1st term
so, 5x divide by 5x^3 which is x^2
step2) distribute to ALL terms
then multiply 4 (your 2nd term) by the x^2 (quotient)
step3) subtract
so the 5x^3 you get from 5x and x^2 is positive... you subtract it from the 5x^3 inside. And your result from distribution should be 4x^2 which you subtract
step4) repeat
and u continue that all the way through!
