Work. Do Not Solve

Multiple Choice

work. Do not solve.
-5x + 9y = -12
-4x - 4y = -32
A) Substitution B) Addition
Answer: B
Write the word or phrase that best completes each statement or answers the question.
-Dmitri needs 9 liters of a 69% solution of sulfuric acid for a research project in molecular biology. He has two supplies of sulfuric acid solution: one is an unlimited supply of the 81% solution and
The other an unlimited supply of the 54% solution. How many liters of each solution should Dmitri
Use?

A) 5.5 L of 81% solution; 3.5 L of 54% solution
B) 4 L of 81% solution; 5 L of 54% solution
C) 4.5 L of 81% solution; 4.5 L of 54% solution
D) 5 L of 81% solution; 4 L of 54% solution