Hi!

<em>Plug in </em>
for 

<em>Multiply </em>
<em>and </em>

<em>Add </em>
<em>and </em>

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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.
The 2nd choice down in correct.
Answer:
let the two numbers be x and y
x+y=45(equation 1)
x-y=5(equation 2)
from equation (1) y=45-x(equation 3)
substitute 45-x for y in equation 2
x-(45-x)=5
x-45+x=5
x+x-45=5
2x-45=5
2x=45+5
2x=50
x=50/2
x=25