If two lines are perpendicular, the statement that must be true is : D. The product of their slopes is -1
Lets say that a line has a slope of 2, the line which perpendicular to that line would have a slope of -1/2
Which means, the product would be 2(-1/2) = -1
hope this helps
The answer is 79 and 80.
x - the number of the first locker
x + 1 - the number of the consecutive locker
Their sum is 159.
x + x + 1 = 159
2x + 1 = 159
2x = 159 - 1
2x = 158
x = 158 / 2
x = 79
x - the number of the first locker: x = 79
x + 1 - the number of the consecutive locker x + 1 = 79 + 1 = 80
Answer:

Step-by-step explanation:
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Answer: 