18 + (-8) + 11
Adding a negative number is the same as subtracting a positive number. So "18-8" is the same thing as "18+ -8".
18 - 8 + 11
10 + 11
21
The answer for number one is -3.938.
For full answer it is found on:
https://www.algebra.com/algebra/homework/Finance/Finance.faq.question.1029380.html
63 degrees, if that angle is 72 that means the other must be 54 (add to 180), and if that angle on the other triangle is 54, the others must be 63 (add to 180).
