Answer:
D. 55%
Step-by-step explanation:
The error range ± 9% means that the range is 9% below 62% or 9% above 62%.
The range is:
(62% - 9%) to (62% + 9%)
53% to 71%.
The only answer between 53% and 71% is 55%.
Answers A, B, C are all greater than 71%.
Answer:
4/7
Step-by-step explanation:
2/7 ÷1/2=2/7 × 2 = 4/7
Hope this helps :D
Note that if

, then

, and so we can collapse the system of ODEs into a linear ODE:


which is a pretty standard linear ODE with constant coefficients. We have characteristic equation

so that the characteristic solution is

Now let's suppose the particular solution is

. Then

and so

Thus the general solution for

is

and you can find the solution

by simply differentiating

.
The answer is 38,400
The scale is 1:40 so the side that is 4 in becomes 160 and the side that is 6 in becomes 240
Multiply 160 and 240 and that is the area of the room
Hope this helps
If you mean "factor over the rational numbers", then this cannot be factored.
Here's why:
The given expression is in the form ax^2+bx+c. We have
a = 3
b = 19
c = 15
Computing the discriminant gives us
d = b^2 - 4ac
d = 19^2 - 4*3*15
d = 181
Note how this discriminant d value is not a perfect square
This directly leads to the original expression not factorable
We can say that the quadratic is prime
If you were to use the quadratic formula, then you should find that the equation 3x^2+19x+15 = 0 leads to two different roots such that each root is not a rational number. This is another path to show that the original quadratic cannot be factored over the rational numbers.