Nolan is standing in a stadium and has the option of running up a staircase or down a staircase for exercise. The function f(x)=\frac{1}{50}\big(\left|4x\righ t|+2x\big)f(x)= 50
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(∣4x∣+2x) will determine how many calories Nolan will burn if he runs up xx steps. Use a negative value for xx if he runs down the stairs. Find and interpret the given function values and determine an appropriate domain for the function.