Find the sum. A. 4x2 – x – 5 B. 10x2 + 7x – 5 C. –10x2 + 7x + 11 D. 4x2 + x – 11
1 answer:
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Answer:
Kevin needs 96 points on his last test to raise his mean test score to 90 points.
Step-by-step explanation:
we know that
The mean score is the total of all scores divided by the total number of tests.
Let
x_1 ----> the score in the first math test
x_2 ----> the score in the second math test
x_3 ----> the score in the third math test
x_4 ----> the score in the fourth math test
we have
After taking the first 3 tests, his mean test score is 88 points
so
----> equation A
How many points does he need on his last test to raise his mean test score to 90 points?
so
----> equation B
substitute equation A in equation B
solve for x_4
Therefore
Kevin needs 96 points on his last test to raise his mean test score to 90 points.