Answer:
21
Step-by-step explanation:
The sum of the angles in a triangle is 180.
- So we know that 42+(5p-7)+(2p-2)=180.
- Since it is addition and subraction, you don't need parentheses. 42+5p-7+2p-2=180.
- Combine like terms, 33+7p-180.
- Subract 33, 7p=147.
- Divide by 7 to isolate p, p=21.
Double check, 42+(5[21]-7)+(2[21]-2)=42+(105-7)+(42-2)=42+98+40=180.
