Answer:
The number of protons is the answer
Answer:
The product is the difference of squares is 
Step-by-step explanation:
Explanation
- The given expression is (x y-9)(x y+9).
- We have to multiply the given expression.
- Square the first term xy. Square the last term 9 .

Answer:
-72
Step-by-step explanation:
The answer is -72 because 8 * -9 = -72, I can't explain it to you any other way ;-;
Distribute
10+4x+4+5
Combine like terms
19+4x
Final answer: 4x+19