Well if Abby is twice the age of her bother and her brother is 9 then she is going to be 18 because 9x2=18, then it says that she is half her dads age so all you have to do is add 18+18 which equals 36
Answer:
4x + 7
Step-by-step explanation:
9x - 5x = 4x
-3 + 10 = 7
Answer:
1885 plate appearances
Step-by-step explanation:
546 plate appearances + 627 plate appearances + 712 plate appearances = 1885 plate appearances
Answer:
60
Step-by-step explanation:
Since this angle is unknown, let's just represent it with the variable "x". So the supplement angle of "x" is essentially, the value of the angle that we need to add to "x" to get 180. In other words let's just say that the supplement angle is "y". This means that: 
. If we subtract x from both sides we can represent "y" or the supplement angle as: 
.
Since it's 660 less than 6 times it's own supplement let's first multiply the supplement by 6
Now let's subtract 660 from it, since it's 660 less
This value should be equal to the angle, which is represented as "x". So let's set it equal to x
Add 6x to both sides
Divide both sides by 7
Answer:
Dimensions of the container:
x = 3 m
y = 6 m
h = 1.1 m
C(min) = 270 $
Step-by-step explanation:
Volume of storage container
V = 20 m³
Let "y" be the length and "x" the width then y = 2*x
V = x*y*h ⇒ V = 2*x²*h ⇒ 20 = 2*x²+h ⇒ h = 10/ x²
Costs:
Total cost = cost of base ( 5*2*x² ) + cost of side with base x ( 2*9*x*h) +
cost of side witn base y =2x (2*9*2x*h)
C(t) = 10*x² + 18*x*h + 36*x*h
C(x) = 10x² + 54*x*10/x² ⇒ C(x) 10*x² + 540 /x
Taking derivatives on both sides of the equation we get:
C´(x) = 20*x - 540/x²
C´(x) = 0 ⇒ 20*x - 540/x² = 0 ⇒ 2x - 54/x² = 0
2x³ - 54 = 0
x³ = 27 x = 3 m
Then y = 2*x ⇒ y = 2*3 y = 6 and h = 10 / x² h = 1.1 m
And the minimum cost is
C (min) = 10*x² + 540/x ⇒ C (min) = 90 + 180
C(min) = 270 $
