I'm not too sure myself (cause Im a learning student myself at the age of 16 and I learn it in a completely different language) I cant really understand c) sorry for my poor english but I think I have gave you enough tips to do c)
Answer:
18
Step-by-step explanation:
-2(3x+4)+7x=10
-6x-8+7x=10
x=10+8
x=18
The answer is 2
Step-by-step explanation: 100% is the highest score you can have . then you have to divide 25 by 100 because 25 is the total amount of questions ,you should get 4,wich means each question is worth 4 points.
18 correct is a score of 72
20 correct is a score of 80
4x2=8 wich you need 8 more to get to 80 from 72
feel free to ask for more help :)