Identify Factors: Identify common factors in each term.We have the polynomial 7z3+14z2−10z−20. We can look for common factors in pairs of terms.The first two terms, 7z3 and 14z2, have a common factor of 7z2.The last two terms, −10z and −20, have a common factor of −10.
Factor by Grouping: Factor by grouping.We group the terms with their common factors and factor them out:7z2(z+2)−10(z+2).Now we can see that (z+2) is a common factor.
Factor Common Binomial: Factor out the common binomial factor.We can now factor out the common binomial factor (z+2) from both groups:(7z2−10)(z+2).
Check Further Factoring: Check for further factoring.The first group, 7z2−10, does not factor further since 7 and 10 have no common factors and the expression is not a difference of squares or any other easily factorable form.The second group, z+2, is already a binomial and cannot be factored further.