To determine which expression cannot be used to find the diver's depth after 5 minutes, we should first calculate her depth after 5 minutes at a rate of 8 meters per minute.
The diver descends at a rate of 8 m/min for 5 minutes. Therefore, her depth will be:
Depth = Rate × Time
Depth = -8 m/min × 5 min = -40 m
Now, let's examine each expression:
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−85: This is a single value and does not represent the calculation for depth after 5 minutes. This expression cannot be used to find her depth.
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−8−8−8−8−8: This represents the depth calculation as -8 added together 5 times, which is a way to express -8 times 5, resulting in -40.
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−8+(−8)+(−8)+(−8)+(−8): This is equivalent to adding -8 five times, which also results in -40, same as the previous one.
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−8(5): This directly represents the calculation of -8 times 5, which equals -40.
Based on this analysis, the expression that CANNOT be used to find her depth after 5 minutes is:
−85