Identify Negative Expression: Since a < 4, we know that the expression inside the absolute value, a−5, will be negative because any number less than 4 minus 5 will be less than 0. Therefore, ∣a−5∣ will be equal to −(a−5) to make it positive.
Rewrite Without Absolute Value: Now we can rewrite the expression without the absolute value: 8a−(−(a−5))−10.
Distribute Negative Sign: Simplify the expression by distributing the negative sign inside the parentheses: 8a+(a−5)−10.
Combine Like Terms: Combine like terms: 8a+a−5−10.
Further Simplification: Further simplification gives us 9a−15.
Final Simplified Expression: Since we cannot simplify any further without a specific value for a, and we are given that a < 4, this is the simplified expression for any a that is less than 4.