Simultaneous equation refer to a pair of equations that are solved at the same time.
<h3>What is a simultaneous equation?</h3>
A simultaneous equation refer to a pair of equations that are solved at the same time.
For problem 1;
x = 4 - y ------ (1)
y^2 = 3x + 19 ----- (2)
Substitute (1) into (2)
y^2 = 3(4 - y) + 19
y^2 = 12 - 3y + 19
y^2 +3y - 31 =0
y = 4.27 or -7.27
x = 4 - 4.27 = 0.27
or
x = 4 - (-7.27) = 11.27
For the second problem;
x = 7 - y
y^2 = 5x - 15
Substitute (1) into (2)
y^2 = 5(7 - y) - 15
y^2 =35 -5y -15
y^2 + 5y - 20 = 0
y =2.62 or -7.62
x = 7 - 2.62 = 4.38
OR
x= 7 - (-7.62) = 14.62
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Since 
represents the number of years passed since 2005, in 2005 we have 
, and in 2015 we have 
. Let 
represent the profits of Jones and Davis, respectively, at year y.
We have
Choosing the best company somehow depends on how much time you can wait: Jones start with a higher value (10 vs 8), but it has a descending trend, because the multiplicative factor 
goes to zero as t grows.
On the other hand, Davis starts with a smaller value, but 
tends to infinity as t grows.
So, if you need an immediate result, the most valuable company is Jones, otherwise you're certain can Davis will eventually become bigger.
More precisely, we have
So, after 11 years, Davis will overcome Jones.
Answer: 63 nurses and 14 doctors
so you know the ratio is 9:2. that means for every 9 nurses there are 2 doctors. i didn't make an equation but i counted it.
if theres 9 (9*1) nurses theres 2 (2*1) doctors
if theres 18 (9*2) nurses theres 4 (2*2) doctors
if theres 27 (9*3) nurses theres 6 (2*3) doctors
you get the point so i multiplied 7 to 9 and 7 to 2, which means:
if theres 63 (9*7) nurses theres 14 (2*7) doctors
i hope this helps :)
<h2>Answer: sometimes it dose that if u have ether not been on brainly in a while or if u do a sertan type of question it logs u out and then you will have to re log in and if it dose that all the time u click on a question you might need to report a bug to brainly hope i <em>helped :)</em></h2>
