2.1 -2.2 Linear Equations and Inequalities Quiz

• No Solution (∅)

• One Solution, -4

• One Solution, 4

• Infinite Solutions (ℝ)

• One Solution, 6

• No Solution (∅)

• One Solution, 0

• Infinite Solutions (ℝ)

• No Solution (∅)

• Infinite Solutions (ℝ)

In a class where the final course grade depends entirely on the average of four equally weighted 100-point tests, Erica has scored, 94, 89, and 78 on the first three.  What range of scores on the fourth test will give Erica a C for the semester (an average between 70 and 79, inclusive)? Assume that all test scores have a non-negative value. 
Express your answer in interval notation. 

• [19, 55]

• [20, 56]

• [21, 57]

• [22, 58]

• (2, 9)

• [-2, 3)

• [9.2)

• Infinite Solutions (ℝ)

• No Solution (∅)

• One Solution, 0

• Infinite Solutions (ℝ)

• One Solution, -4

• No Solution (∅)

• One Solution, -9