Which shows how to solve the equation negative 4 fifths x is equal to 80 for x in one step?

To isolate x in −4/5 x = 80, multiply both sides by the reciprocal of −4/5, which is −5/4. This makes the coefficient of x equal to 1, so the one-step setup is −4/5(−5/4)x = 80(−5/4). That is choice B.

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