1. **State the problem:** Factor the linear expression $20x - 90$. 2. **Recall the factoring rule:** To factor an expression, find the greatest common factor (GCF) of all terms and factor it out. 3. **Find the GCF:** The terms are $20x$ and $-90$. The GCF of 20 and 90 is 10. 4. **Factor out the GCF:** $$20x - 90 = 10(\cancel{2}x - \cancel{9})$$ Here, we cancel the common factor 10 from both terms inside the parentheses. 5. **Write the final factored form:** $$20x - 90 = 10(2x - 9)$$ This is the expression factored as a product with a whole number greater than 1. **Answer:** $10(2x - 9)$