To solve with Elimination:
Write the equations under one another, like this:
2x - y = -1
+ 3x + 4y = 26
Ideally, we would like for one of the variables to be eliminated when we add vertically (straight down). But if we add them as they are this does not happen. We must manipulate one of the equations so that it will happen. Again, you can try to eliminate either x or y. I always look for a term that has a coefficient of 1 (or negative 1). So, let's use that y from the first equation again.
If the coefficient of the y in the other equation is POSITIVE 4, then I need the coefficient from the first equation to be its opposite, NEGATIVE 4. To do this, simply multiply the first equation by 4, this will create MAGIC!
4( 2x - y = -1)
+ 3x + 4y = 26
Be certain to Distribute across the entire first equation, so multiply all three terms by 4.
8x - 4y = -4
+ 3x + 4y = 26
Now add straight down (vertically). The y term will be eliminated.
11x = 22
Divide both sides of the equation by 11.
x = 2
Almost there! Now, substitute the 2 in for x in either of the original equations. Either one will work. I'm gonna use the second equation.
3x + 4y = 26
3(2) + 4y = 26
6 + 4y = 26
Subtract 6 from both sides of the equation.
4y = 20
Divide both sides of the equation by 4.
y = 5
That's it! There it is again. Put it all together. If x = 2 and y = 5, then the solution is the ordered pair, (2,5).
Answer:
vertex(-3,27)
Step-by-step explanation:
f(x)= x^2+ 6x + 36 ( a=1,b=6,c=36)
V(h,k)
h=-b/2a=-6/2=-3
k=f(-3)=3²+6(-3)+36
f(-3)=9-18+36=27
vertex(-3,27)
Answer:
this system has two solutions
Answer:
1. 3413
2. 4886
3. 114
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean 
and standard deviation 
, the z-score of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Mean is 400 hours and the standard deviation is 50 hours
This means that 
1. Between 350 and 450 hours:
The proportion is the pvlaue of Z when X = 450 subtracted by the pvalue of Z when X = 350.
X = 450:
has a pvalue of 0.8413.
X = 350:
has a pvalue of 0.1587.
0.8413 - 0.1587 = 0.6826
Out of 5000:
0.6826 out of 5000. So
0.6826*5000 = 3413
3413 are expected to last between 350 hours and 450 hours.
2.more than 300 hours
The proportion is one subtracted by the pvalue of Z when X = 300.
has a pvalue of 0.0228
1 - 0.0228 = 0.9772
Out of 5000:
0.9772of 5000 is
0.9772*5000 = 4886
4886 are expected to last more than 300 hours.
3.less than 300 hours
4886 are expected to last more than 300 hours, so 5000 - 4886 = 114 are expected to last less than 300 hours.
