The mean of n numbers is the sum of the numbers divided by n.
You have a mean score of 84 after taking 5 tests. Let x be the sum of scores.

You scored a total of 420 points on five tests.
You need to have a mean score of 85 after taking 6 tests. Let y be the score you need to obtain. Your total score on 6 tests is 420+y.

You need to score 90 points on the sixth test.
Answer:
answer of your question is
-x= -7
Answer:
I think the answer is y = 3x - 10
Step-by-step explanation:
Answer:

Step-by-step explanation:
We need to find the solution to the following system of equations:
and 
By plugging the value of 'y' into the first equation we have that:
⇒ 
Solving for 'x' we have:

So, the solution to the system of equation is: (37.5, -30)
Answer: 4 months
Step-by-step explanation:
$75 + $152X = 683
That's the equation you need to set up, with X being the number of months.
To solve, first subtract 75 from both sides.
$152x = 608
Then, divide each side by 152
X = 4
The answer is 4 months.