Solve the simultaneous equations 2x+3y=13 4x-y=-2
1 answer:
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Answer:
the middle 50% of most lengths of pregnancies ranges between 255.62 days and 274.38 days
Step-by-step explanation:
Given that :
Mean = 265
standard deviation = 14
The formula for calculating the z score is
x = μ + σz
At middle of 50% i.e 0.50
The critical value for
From standard normal table
+ 0.67 or -0.67
So; when z = -0.67
x = μ + σz
x = 265 + 14(-0.67)
x = 265 -9.38
x = 255.62
when z = +0.67
x = μ + σz
x = 265 + 14 (0.67)
x = 265 + 9.38
x = 274.38
the middle 50% of most lengths of pregnancies ranges between 255.62 days and 274.38 days
If you're completing the square the answer is in the image.
expression
x^2 + 5x - 5=ax^2+bx+c
a=1, b=5, c=-5, and you can solve it that way.
