Answer:
Step-by-step explanation:
Information given
represent the sample mean
population mean (variable of interest)
s=5 represent the sample standard deviation
n=130 represent the sample size
For this case we can't set a margin of error just with a % since they not specify 1.13% respect to something for this case we can omit this value
Confidence interval
The confidence interval for the mean is given by the following formula:
(1)
The degrees of freedom are given by:
The Confidence level is 0.99 or 99%, the significance would be
and
, and the critical value would be
And replacing we got:
Let:
x= quarters
y= dimes
x+y=67
and
.25x+.10y=12.40
x=67-y
.25(67-y)+.10y=12.40
16.75-.25y+10y=12.40
16.75-.15y=12.40
Lets rearrange this:
-.15y+16.75=12.40
-16.75 -16.75
-.15y=-4.35
the negatives cancel out
.<u>15y</u>=<u>4.35
</u>.15<em /><em> <u /></em>.15
y=29
Back to the original x=67-y
x=67-29
x=38
So,
x=38
y=29
<em />
For this case we have the following system of equations:

We can write a system of equivalent equations.
For this, it is enough to multiply one of the two equations by a scalar.
Multiplying the equation 1 by 2, we have:

Therefore, the new system of equations is:

Answer:
A system that is equivalent is:
D) 
Answer:
-3
Step-by-step explanation:
answer must be negative since graph opens downward
value of 'a' must must be less than -1