Question

Betty's grade in science class is affected by the number of missing assignments. The table below shows the science grade percentage for a given number of missing assignments.
Number of missing assignments: 3,5,7,9
Science grade%: 80,70,60,50
The equation for the given table is y=-5x+95. If Betty is missing 15 assignments, what's the [percentage of her grade in science class?

What is the rate of change?

Answer 1

Hi!

$y=-5x+95$

Plug in $15$ for $x$

$y=-5(15)+95$

Multiply $-5$ and $15$

$y=-75+95$

Add $-75$ and $95$

$y =15$

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Betty's percentage is 15%.

The rate of change is the amount it changes for every missing assignment, therefore it would be -5.