To solve using completing square method we proceed as follows:
x^2-10x+8=0
x^2-10x=-8
but
c=(b/2)^2
c=(10/2)^2=25
thus we can add this in our expression to get
x^2-10x+25=8+25
factorizing the LHS we get:
(x-5)(x-5)=33
(x-5)^2=33
getting the square roots of both sides we have:
x-5=+/-√33
x=5+/-√33
8z-8=6z+8
8x-6z=8+8
2z=16
Z=8
2. 3. 5. are correct
1. and 4. are actually interchanged
1. Answer: given: an average of 28 pounds
a.
Find z values corresponding to 27 and 31:
z=%2827-28%29%2F2=-1%2F2=-0.5
z=%2831-28%29%2F2=3%2F2=1.5
Find the area between z+=+-0.5 and z=+1.5
Table E gives us an area of 0.9332-0.30=0.6247=> The probability is 62.47%
b.
Find z values corresponding to 30.2
z=%2830.2-28%29%2F2=2.2%2F2=1.1 Find the area to the right of z+=1.1
it gives you an area of 0.1357=> The probability is 13.57%
It so big problem
but you can do it
