Answer:
52
Step-by-step explanation:
Given that :
Mean (m) = 78
Standard deviation (s) = 13
Score that is 2 standard deviations below the mean
Using the relation :
Zscore = (x - m) / s
2 standard deviations below the mean means a Zscore of - 2
Hence,
-2 = (x - 78) / 13
Cross multiply
-2 * 13 = x - 78
-26 = x - 78
x = - 26 + 78
x = 52
Score which is 2 standard deviations below the mean is 52
Answer:
x=5
Step-by-step explanation:
7x - 4y = 23 and x + y = 8
Multiply the second equation by 4
4x + 4y = 32
Add this to the first equation
7x - 4y = 23
4x + 4y = 32
------------------------
11x = 55
Divide each side by 11
11x/11 = 55/11
x = 5
Answer:
a mathematical sentence thar has an equal sign
Answer:
h(x) = -16x² + 192x + 208
784ft
6 sec
13 sec
Step-by-step explanation:
a)
h(x) = -16x² +vx + h
here v represent velocity
represent initial height of launch
h(x) = -16x² + 192x + 208
b)
h(x) = -16x² + 192x + 208
here a = -16
b = 192
c = 208
x = -b/2a
= -192/2(-16)
= 6
plug this value in the equation
h(x) = -16(6)² + 192(6) + 208
= 784ft
e)
Plug h(x)=0 in the equation
0 = -16x² + 192x + 208
divide equation by -16
x² - 12x - 13 = 0
Factors
1x * -13x = -13
1x - 13x = -12
Factorised form
x² - 12x - 13 = 0
x² + x - 13x - 13 = 0
x(x+1) -13(x+1) = 0
(x+1)(x-13) = 0
x = -1
x = 13
Since time can not be negative so we will reject x = -1
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