Someone pls help giving brainlist to the best answer :)

A

Step-by-step explanation:

Isabella started with 10 points. We know that the first value of this will be 10. Then, she loses 20 points. This is represented with -20. Finally, she wins 45 points, which is shown by writing +45.

10 - 20 + 45

:)

Have a nice day!

c.

step-by-step explanation:

she should of added 9^2 and 12^2. that is because it is a^2+b^2=c^2. c^2 is the hypotenuse and should always be bigger than the other two numbers. which is why she should of added 9 squared and 12 squared together instead of 15 squared.