Answer:
Step-by-step explanation:
The fraction remaining at turn-on is found by setting x = 0.
y = -0.02·0 +0.60 = 0.60 = 60%
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The number of hours the battery will last is found by setting y = 0.
0 = -0.02x +0.60
0 = -x + 30 . . . . . . . multiply by 50
x = 30 . . . . . . . . . . . add x
The battery will last 30 hours after you turn on the phone.