Answer:
D
Step-by-step explanation:
38+(-18) can be changed to 38-18 and the answer will still be the same
Answer:
If
and
, then 
Step-by-step explanation:
This is a problem that utilizes both substitution and the order of operations.

Answer:
2,800 Books to be the same.
We can solve this problem by the rule of three.
1000 protons=10³ protons
1 proton------------------2.53*10⁻³⁷g
10³ protons---------- x
x=(10³ protons * 2.53*10⁻³⁷) / 1 proton=2.53*10⁻³⁷⁺³ protons=
=2.53*10⁻³⁴ protons
answer: 2.53*10⁻³⁴ protons
Is that a with 4 vertices ,,,check your question