In a class in which the final course grade depends entirely on the average of four equally weighted 100-point tests, Harold has scored 92, 84, and 85 on the first three. What range of scores on the fourth test will give Harold a C for the semester (an average between 70 and 79, inclusive)? Assume that all test scores have a non-negative value.

Between 19 and 55, inclusive

Step-by-step explanation:

70 < Average < 79 (inclusive)

4×70 < sum < 4×79 (inclusive)

280 < sum < 316

280 < 92 + 84 + 85 + X < 316

280 < 261 + X < 316

19 < x < 55

Fourth score can be between 19 and 55, inclusive

5x+40

5(x + 8)

7x - 49

7(x - 7)

18x + 9

9(2x + 1)

15x - 10

5(3x - 2)

step-by-step explanation:

for number one all you have to do is factor 5 out of 5x + 40

for number 2 factor 7 out of 7x - 49

for number three factor 9 out of 18x + 9

for number four factor 5 out of 15x - 10

whats the