What is y=-10x's constant of proportionality and how would describe a graph's constant rate of change.

Okay, so here, we know that -10 is the slope, therefore, it is also the constant of proportionality. 

'x' is the unknown value, that tells us to multiply by -10. 

So, on a graph, we would consider that per unit, it would decrease by -10, since its a negative slope. 

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A. y=12x+35

Step-by-step explanation:

i think that is the answer because Y is the solution and X represents the cost of each lesson, so it is 12x and then you add 35 to it.