Answer: A
Step-by-step explanation:
2x²-2x-9=0
this is a quadratic equation so we will use the quadratic formula .
Δ= b²-4*a*c
let's calculate Δ to khow how many solutions this equations have .
Δ= (-2)²-4*2*(-9)
= 76
we notice that 76>0
so this equation has two solutions : (-b-√76)/4 and (-b+√76)/4
- let's calculte the values :
- (-b-√76)/4=
(-b+√76)/4=
the trick here is to notice that :
= 
= 
= 2
Now we will simplify Δ by factoring by 2
= 
so the answer is a .
Answer:
Yes, it's also true about the confidence interval method.
Step-by-step explanation:
The confidence interval includes all the null hypothesis values for the population mean that would be accepted by the hypothesis test at the significance level of 5%. Now, it means this assumes a two-sided alternative.
Now, when testing claims about
population proportions, the critical method and the P-value method are equivalent due to the fact that they always produce the same result. Similarly, a conclusion based on a confidence interval estimate will be the same as a conclusion based on a hypothesis test.
So, Yes the confidence interval method and the P-value or critical methods will always lead to the same conclusion when the tested parameter is the standard deviation.
The dependent Variable would be
D. 4
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<span>You are told that the two angles are supplementary. That means that when you add the measure
of angle A (call it mA) and the measure of angle B (call it mB) the resulting sum is 180 degrees.
This relationship can be written in equation form as:
.
mA + mB = 180
.
You are also told that the two angles are congruent. This means that their measures
are equal. You can write this relationship as the equation:
.
mA = mB
.
From this second equation you can see that wherever you have mA you can substitute mB
in its place because they are equals. So go back to the equation:
.
mA + mB = 180
.
In place of mA substitute mB. This makes the equation become:
.
mB + mB = 180
.
On the left side you can see that the sum is 2 times mB or 2*mB. Make this simplification
to get:
.
2*mB = 180
.
To solve for mB divide both sides of this equation by 2. When you do that division the
equation reduces to:
.
mB = 180/2 = 90
.
This tells you that the measure of angle B is 90 degrees, and that means that the measure
of angle A is also equal to 90 degrees because the two angles are congruent.
I hope this helps!</span>
X + y + z = 27
x = 2z
y = 3 + z
2z + 3 + z + z = 27 ; 4z = 24; z = 6 youngest
x = 12 oldest
y = 9 middle one
