The best and most correct answer among the choices provided by the question is the first choice. The first step to do during the substitution method is to s<span>olve the top equation for x. </span><span>I hope my answer has come to your help. God bless and have a nice day ahead!</span>
Answer:
1. They help you with estimation
2. It makes numbers simpler and easier to do
3. Makes mental maths much quicker
50.625 is the answer You should round it though
I'm not sure of the answer by paper but I suggest www.desmos.com it will help you with problems like these. if you're not sure how to use it, message me and I'll help you