Answer:
66
Step-by-step explanation:
Use the formula for the mean of a set of numbers:
sum of the numbers
average = --------------------------------
count of numbers
Here we know that the average mark was 68, so we can write:
75 + 62 + 84 + 53 + x
average = 68 = ----------------------------------
5
or 274 + x
68 = -------------------
5
Solving for x, we multiply both sides by 5: 340 = 274 + x.
Subtracting 274 from both sides effectively isolates x:
340 = 274 + x
- 274 -274
------------------------
66 = x
The fifth student's mark was 66.
Answer:
centre = (- 3, - 2) , radius = 1
Step-by-step explanation:
The equation of a circle in standard form is
(x - h)² + (y - k)² = r²
where (h, k) are the coordinates of the centre and r is the radius
Given
x² + 6x + y² + 4y + 12 = 0 ( subtract 12 from both sides )
x² + 6x + y² + 4y = - 12
Use the method of completing the square on the x and y terms
add ( half the coefficient of the x/ y terms )² to both sides
x² + 2(3)x + 9 + y² + 2(2)y + 4 = - 12 + 9 + 4
(x + 3)² + (y + 2)² = 1 ← in standard form
with centre = (- (- 3), - (- 2)) and r² = 1, that is
centre = (- 3, - 2) and radius = 1
Answer:
its D Q and O
Step-by-step explanation:
Answer:
3.00156378e13
Step-by-step explanation:
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Answer:
Step-by-step explanation:
