ElectricPavlov

x+7 <5    yields    x < -2

x+7>-5   yields     x > -12

x+7>2   yields   x > -5

x+7 <-2 yields   x < -9

combining     ( -12,-9) U ( -5,-2)

a +n  = 4 (b-n)       a = 4b - 5n     and

a-n = 3 (b+n)         a = 3b + 4n        multiply THIS equation by 1.25

                             1.25 a = 3.75 b + 5n     add this equation to the top one

2.25 a = 7.75b      divide both sides by b

2.25 a/b = 7.75    divide both sides by 2.25

a/b = 7.75/2.25 = 31/9 

sqrt (( -5- -1)^2 +  (1- - 3)^2 )

 sqrt ( 16 + 16) = sqrt 32    =   4 sqrt2

The AMOUNT of chocalate remains the same    .06 (10) = .6 l

The final mix is 10 + 50 = 60 liters     .6 liters is choc    .6 / 60 = 1%

15.  15.   15.    16.          16 wins

First one    t = r/(r-3)    multiply both sides by (r-3)

tr - 3t  = r       subtract   tr from both sides

-3t = r - tr

-3t = r (1-t)

-3t/(1-t) = r

Hour hand starts at 30 degrees and moves 1/2 degree per minute

minute hand moves 6 degrees per minute

30 + 1/2x   =   6x    where x is the minutes after 1:00

30 = 5.5x

x = 5.4545 minutes       or      1:05:27     This is when they overlap (forming a straight line)

If you want when they form an end-to-end straight line:

30 + 1/2x  + 180 = 6x

210 = 5.5x

x = 38.18           ~~   1:38:11

200-24-2t = 140

t = 18 m^2

a+b =- 4       so    a = - 4-b

ab = -9       sub in for a

(-4-b)b = -9

-4b-b^2+9 = 0

-b^2-4b+9 = 0           Quadratic Formula   shows     and b =  −5.60555   1.60555          or    -2 +-sqrt13