We write the equation in terms of dy/dx,
<span>y'(x)=sqrt (2y(x)+18)</span>
dy/dx = sqrt(2y + 18)
dy/dx = sqrt(2) ( sqrt(y + 9))
Separating the variables in the equation, we will have:
<span>1/sqrt(y + 9) dy= sqrt(2) dx </span>
Integrating both sides, we will obtain
<span>2sqrt(y+9) = x(sqrt(2)) + c </span>
<span>where c is a constant and can be determined by using the boundary condition given </span>
<span>y(5)=9 : x = 5, y = 9
</span><span>sqrt(9+9) = 5/sqrt(2) + C </span>
<span>C = sqrt(18) - 5/sqrt(2) = sqrt(2) / 2</span>
Substituting to the original equation,
sqrt(y+9) = x/sqrt(2) + sqrt(2) / 2
<span>sqrt(y+9) = (2x + 2) / 2sqrt(2)
</span>
Squaring both sides, we will obtain,
<span>y + 9 = ((2x+2)^2) / 8</span>
y = ((2x+2)^2) / 8 - 9
3 1/7 Because there are three multiples of 7 and 1 remainder.
The required percentage error when estimating the height of the building is 3.84%.
<h3>How to calculate the percent error?</h3>
Suppose the actual value and the estimated values after the measurement are obtained. Then we have:
Error = Actual value - Estimated value
Given that,
An estimate of the height, H meters, of a tall building can be found using the formula :
H = 3f + 15
where the building is f floors high.
f = 85
The real height of the building is 260 m.
H = 3f + 15
Put f = 85 in the above formula
H = 3(85) + 15
H = 270 m
Error,

So, the required percentage error is 3.84%.
Learn more about percentage error;
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20.75 because if you add 4.85+7.95+7.95 add that you get 20.75
Answer:
$13.12 per hour
Step-by-step explanation:
Take the total pay and divide by the number of hours
$282.08/21.5 hours
$13.12 per hour