ElectricPavlov

y = 18/x

First get everything one side

x^2-2x-5=0

x^2-2x = 5         Take 1/2 of the 'x' coefficient and square it and add it to both sides

x^2 - 2x +1 = 5 + 1

(x-1)^2 = 6

x-1 = +-sqrt 6

x= 1 + sqrt 6     and  1- sqrt 6

42 pence  / 100gm    x    600 gm =     42 x 600 / 100    pence   =  ????       Use the calculator

I am not sure this is possible.....by definition a parabola is the set of points equidistant from the point called a focus and a line called the directrix.   if the focus is at the vertex, the directrix would have to intersect this point also    -p = 0

then you don't have a parabola, you have a straight line......

    Thought about this while on a long bike ride yesterday, and I cannot make this work.....IF you move the focus off of the vertex, I think I can make it work......

   Anyone else?

Where is the rest of your question??

7 (n+6)      Use distributive property

= 7n + 42

3x + 4x  =  7x  

First , 75% of 300 employees is   .75 x 300 = 225

then

225 = 300/(1+299 e(-.3t) )     re-arranging

1+299 e(-.3t) = 300/225

1+299 e(-.3t) = 1.3333333

299 e(-.3t) = 0.333333

e(-.3t) = .3333333/299          Now take the ln of both sides

-.3t = - 6.7990558

t= 22.66 minutes

Time involved = 900 to 1045 = 1.75 hr

x= speed of slower cyclist

1.75 hr * x = distance of slower cyclist

x+5 = faster cyclist's speed

1.75 hr *(x+5)  = distance of faster cyclist

the two distances added together = 47.25

1.75 x  + 1.75(x+5) = 47.25

3.5x + 8.75 = 47.25

3.5x = 38.5

x=11 km/hr = slower cyclist

x=5=16 km/hr = faster cyclist

If you look at a Bell curve, the FIRST standard deviation covers 34%   the second 14% the third 2%

A 1.7 to 1.9  is THREE standard deviations (1.7 + 3 (.064) = ~1.9)     so

       34+14+2 =   50 %

D  1.8 is ONE standard deviation above the mean for 34%  all of the SHORTER than the mean covers another 50%

       50% + 34% = 84% 

See below:  (ignore the 'same as others' 'less than others'  etc)  Just look at the numbers on the bottom