CPhill

1+7u=25    subtract 1 from both sides

7u = 24     divide both sides by 7

u = 24 / 7

Let M be the miles that will equate the cost.....and we have......

17 + .07M =  22 + .05M     subtract .05M and 17 from both sides

.02M  = 5     divide both sides by  .02

5 / .02   = M = 250 miles

The "Blue Meanies" transported Math to Earth many thousands of years ago when they landed-  by spaceship - near Chicago..........since then..... "Math"has been nothing but a plague-filled, Pandora's Box to humankind, everywhere.........!!!!!

(1/(e^x - e^-x)) = 2   

Notice that we can invert both sides and get :

(e^x - e^-x)  = 1/2     multiply through by 2e^x  

2e^2x - 2 = e^x      subtract e^x from both sides and rearrange

2e^2x - e^x - 2  = 0    this will not factor......let e^x  = y   and we have

2y^2 - y - 2 = 0     and the solutions for this are....y ≈ -.78078     and y  = 1.2808

Therefore, e^x = -.78078 (impossible).......  or e^x = 1.2808

So

e^x  =  1.2808     which means that x = ln 1.2808  = about .2475

x + 5x + 8x - 5 = 317   simplify on the left

14x - 5 = 317    add 5 to both sides

14x = 322     divide both sides by 14

x = 23 in

5x = 5(23)  = 115 in

8x - 5 = 8(23) - 5 =  179 in

I believe that the question is : find two consecutive wole numbers that the sqrt(46) lies between.......

In that case.....the answer is 6 and 7

sqrt(36) = 6

sqrt(49) = 7

And sqrt(46) lies between these

There may be more than one answer for this.......according to whether the growth rate is considered to be lnear, exponential, etc.

Assuming it's linear, the circumference changes by [150.42- 75.36] / [2 - 1]  = 75.06 in each week

See my answer....here.......http://web2.0calc.com/questions/please-help_54167

Let N  be the original number

So......

2N + 28 = (4/9)N     subtract (4/9)N and 28 from both sides

2N - (4/9)N = -28     get a common denominator on the left

(18/9)N - (4/9)N  = -28

(14/9)N = - 28      multiply both sides by 9/14

N = -28 (9/14)   =   -2 * 9   = -18  is the original number

-6>x-8   add 8 to both sides

2 > x    or, put another way, x < 2