Answer:
6 knots
Step-by-step explanation:
Let the speed be v knots
then time taken to cover 500 M = 500 / v hrs
fuel consumption /hr = 216 + 0.5v^3
let F be the fuel consumption for trip
= [500/v][216 + 0.5v^3]
= 500[216/v + 0.5v^2]
dF/dv = 500[ - 216/v^2 + v]
d^2F/d^2v = 500[432/v^3 + 1] , i.e. +ve
so setting dF/dv will give a minima
500[ -216/v^2 + v] = 0
or v = 216/v^2
or v^3 = 216
solving, we get v = [216]^(1/3) = 6 knots
Find AC using Pythagorean theorem
6^2 + 8^2 = AC^2
36 + 64 = AC^2
100 = AC^2
10 = AC
6+8+10 = 24
24/60 = 2/5
10/x = 2/5
50 = 2x
25 = x
Answer: x = 9
Mel's mistake was in the last step, she multiplied by 2 instead of dividing by 2
Step-by-step explanation:
2x + 1 = 19
Subtract 1 from each side
2x = 18
Divide by 2
x = 9
15. 
Step 1: Distribute the subtraction sign to all the numbers in the second set of parentheses...


Step 2: Combine like terms (
's go with
's)




Step 3: Combine like terms (
's go with
's)




Step 4: Combine like terms (normal numbers go with normal numbers)

1 + 2
3

You were correct!
16. 
I don't really know how to explain this one but I got: (7m-6n)(7m-6n)
Step-by-step explanation:
the eqn is 3x-2y+10=0
slope m=-3/-2=3/2 (m=(-xcoeff/ycoeff)
eqn is
y-y1=m(x-x1)
y+5=3/2(x-2)
2y+10=3x-6
3x-2y-16=0