If x=9 and y=−2, evaluate the following expression : 6x−8y
2 answers:
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Answer:
Step-by-step explanation:
When we take an average of something, we have to add up all the data on the somethings and then divide by the number of somethings we have. Ed takes 5 tests, and we have scores for them; we also have his current average. What we don't know for sure are 2 of the 5 test scores, but we have enough to determine what they are.
If one test has a score of x, and the other test is 3 points less than that, the score on that last test is x - 3. Putting all of that together into an average problem:
and simplfiying a bit:
. Multiply both sides by 5 to get
256 + 2x = 450; subtract 256 from both sides to get
2x = 194 and divide by 2:
x = 97
The one test score was a 97 and the other one, which was 3 less than that, was a 94.