Answer:
The answer is B.
Step-by-step explanation:
X= 9th student test score
Add the 9 test scores and divide that total by 9 to equal the average.
(56 + 92 + 78 + 64 + 85 + 83 + 91 + 77 + x)/9= 78
add in parentheses
(626 + x)/9= 78
multiply both sides by 9
626 + x= 702
subtract 626 from both sides
x= 76
ANSWER: 76 is the score needed by the 9th student for a mean of 78.
Hope this helps! :)
Answer:
a-x
b-/
Step-by-step explanation:
64/4x4=64
625x25/25=625
3x − y = 9
y = −2x + 11
3x − (−2x + 11) = 9
3x + 2x - 11 = 9
5x = 9 + 11
5x = 20
x = 4
y = −2x + 11 = -2*4+11 = 3
<span>(4, 3)</span>
