[Math] How to solve Absolute Value Inequality: |x-1| ≥ 3-x

absolute valuealgebra-precalculusinequality

I am learning the topic of solving absolute value inequality question. I had mostly understood the steps in order to solve for an inequality. However, I'm still clueless of a step to solve the inequality below:
Which is: Why does $ 3-x \ge 0$? I notice that 3-x is clearly not inside a radical, so it shouldn't have that requirement. Am I right?

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Best Answer

Solve two separate cases.

Case 1: $x \ge 1$. Then solve $x-1 \ge 3-x$ to get $x \ge 2$.

Case 2: $x < 1$. Then solve $1-x \ge 3-x$ which is never true.

Hence the solution is $x \ge 2$.