Answer:
x^2 -x -2 = (x -2)(x +1)
Step-by-step explanation:
To factor x^2 -x -2, you look for factors of -2 that have a sum of -1:
-2 = (-1)(2) = (1)(-2) . . . . . the latter pair has a sum of -1
Then these are the constants in the binomial factors:
x^2 -x -2 = (x +1)(x -2)
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<em>Comment on the question</em>
The fact that x^2 +3x -4 is modeled with algebra tiles seems to be irrelevant to the question that is actually asked.
Answer:
a) 0.2416
b) 0.4172
c) 0.0253
Step-by-step explanation:
Since the result of the test should be independent of the time , then the that the test number of times that test proves correct is independent of the days the river is correct .
denoting event a A=the test proves correct and B=the river is polluted
a) the test indicates pollution when
- the river is polluted and the test is correct
- the river is not polluted and the test fails
then
P(test indicates pollution)= P(A)*P(B)+ (1-P(A))*(1-P(B)) = 0.12*0.84+0.88*0.16 = 0.2416
b) according to Bayes
P(A∩B)= P(A/B)*P(B) → P(A/B)=P(A∩B)/P(B)
then
P(pollution exists/test indicates pollution)=P(A∩B)/P(B) = 0.84*0.12 / 0.2416 = 0.4172
c) since
P(test indicates no pollution)= P(A)*(1-P(B))+ (1-P(A))*P(B) = 0.84*0.88+ 0.16*0.12 = 0.7584
the rate of false positives is
P(river is polluted/test indicates no pollution) = 0.12*0.16 / 0.7584 = 0.0253
I=PRT
r=rat
P=present amount
I=interst
t=time in yeare
2 years
16%
3000
I=2*3000*0.16
I=$960
Answer:
0.025
Step-by-step explanation:
