Answer:
Step-by-step explanation:
Answer:
The answer is (x + 3) (x - 7) = 0
Step-by-step explanation:
x² - 4x = 21
x² - 4x - 21 = 0
x² - 7x + 3x - 21 = 0
x(x - 7) + 3(x - 7) = 0
(x + 3) (x - 7) = 0
Thus, The answer is (x + 3) (x - 7) = 0
<em><u>-TheUnknownScientist</u></em>
Answer and Step-by-step explanation:
a)
expected value for the difference in sample means=3.5-3.2=0.3
b)
standard deviation of the sampling distribution of the difference in sample means
=sqrt((0.5^2/40)+(0.8^2/40))
=0.1492
c)
z=(0.3-0)/0.1492
z=2.01
P(z>2.01)=0.0222
