Social Work homework help. 1. Detail, in your own words why the parentheses are needed when evaluating 2 + (3*4) or (2*3) + 4.2. Discuss why -a2 is always negative (a ? 0) and why (-a)2 is always positive.3. Who invented the customary +, -, ×, and ÷ symbols? In what publication did they first appear? We also use the diagonal bar to denote fractions example a/b. Who were the first users of the diagonal bar? From what did the diagonal bar evolve?4. Why do you think a/0 is not defined?5. Explain in your own words how you verify and answer in a word problem.6. Write in your own words the difference between an expression and an equation.7. What is the procedure to write a number in scientific notation? What are the advantages and disadvantages of writing numbers in scientific notation?8. Explain the difference between product rule and power rule.