- (1 + 7x) - 6(- 7 - x) = 36
- 1 - 7x + 42 + 6x = 36
41 - x = 36
- x = - 5
x = 5
Jada sells at $5 per kilogram and buys at $2.50
GRAPHING CONS
1) hard to graph by hand. Often you need a graphics calculator or a computer software like maple or matlab. Or the graph has to be given.
2) hard to tell the exact solution, just by observing point of intersection. for example if x = 2.8675, the viewer would say x= 3.
3) sometimes not easy to decide the axis window of y and x axis. For example if the solution is very large like x = 100000 and your graph ends at x = 100, you cannot see the solution
SUBSTITUTION CONS
1) Becomes tedious if a system has too many equations or variables
ELIMINATION PROS/CONS
1) basically same as substitution
Answer:
<u>(3); (-1/2); (-4)</u>
Step-by-step explanation:
First, you should convert the equation into cubic form.
r(x)=(x^2+x−12)(2x+1)
<u>2x^3 +3
x^2
− 23x− 12=0</u>
Next, use the rational roots test to find the first root.
<u>(-1/2) </u>
Using the factor theorem you can find the other roots.
<u>(3)</u> <u>(-4)</u>
Answer:
The mean life time of the bulbs is approximately 739 hours
Step-by-step explanation:
Here, we want to calculate the mean life time
From the question, 95% of the bulbs die before 920 hours
What this mean is that the probability that a bulb will die before 920 hours is 95% = 95/100 = 0.95
Now, we need the z-score that is exactly equal to this value
Using the standard normal distribution table, the z-score corresponding to this probability value is 1.645
Mathematically;
z-score = (x-mean)/SD
In this case, x is 920, SD is standard deviation which is 920 hours
thus, we have it that;
1.645 = (920-mean)/110
110(1.645) = 920 - mean
180.95 = 920 - mean
mean = 920- 180.95
mean = 739.05
