Answer:
k = 7d
Explanation:
The standard form of an equation is :
y = mx + b
Here, the variables for y and x are k and d respectively.
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It is given that Brian runs 7 kilometers each day. Hence, that is our rate of change, m. The value of b will be 0 as he starts from 0 km.
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So, the equation is :
k = 7d