Answer:
C
Step-by-step explanation:
So we need to understand what is rational numbers?
Rational number which can be written under this form: 
when x any are both integers and y
The question here is : Which property would be useful in proving that the product of two rational numbers. In math, when we talk about the product of at least two number, it implies to the multiplication in the operation.
Here, only answer C: 
with the condition 
and a, b, c and d are integers. Product of two integers is always an integer..
An ant on the ground is 22 feet from the foot of a tree. She looks up at a bird at the top of the tree, and her line of sight makes 30 degrees with the ground. How far is she from the top of the tree? (Hint: Find x.)
33.6 feet
Using Laplace transform we have:L(x')+7L(x) = 5L(cos(2t))sL(x)-x(0) + 7L(x) = 5s/(s^2+4)(s+7)L(x)- 4 = 5s/(s^2+4)(s+7)L(x) = (5s - 4s^2 -16)/(s^2+4)
=> L(x) = -(4s^2 - 5s +16)/(s^2+4)(s+7)
now the boring part, using partial fractions we separate 1/(s^2+4)(s+7) that is:(7-s)/[53(s^2+4)] + 1/53(s+7). So:
L(x)= (1/53)[(-28s^2+4s^3-4s^2+35s-5s^2+5s)/(s^2+4) + (-4s^2+5s-16)/(s+7)]L(x)= (1/53)[(4s^3 -37s^2 +40s)/(s^2+4) + (-4s^2+5s-16)/(s+7)]
denoting T:= L^(-1)and x= (4/53) T(s^3/(s^2+4)) - (37/53)T(s^2/(s^2+4)) +(40/53) T(s^2+4)-(4/53) T(s^2/s+7) +(5/53)T(s/s+7) - (16/53) T(1/s+7)
Answer:
The answer is 13.50x
Step-by-step explanation:
81 / 6=13.5 per week
