ElectricPavlov

288/1800  =   4/25   =   .16   = 16 percent     

All of the previous posting stuff still applies EXCEPT this is the new cost equation

71850 = 45c + 120c+   50 ( 1350 - c - 2c)

71850 = 165c + 65000-150c

c = 290

w=2c=580

s= 480 acres

Multiply first equation  x 3   to get   3x^2 - 3y = 21   and add it to second equation to get

5x^2 =45   divide by 5

x^2 = 9      x =3

substitute x=3 into one of the equations

the first one    3^2-y = 7      9-y = 7     -y = -2   y=2

SO:    x,y  =  3,2

As a check substitute these values into equation 2

2(3^2) + 3(2)  =  24 ??

18 + 6 = 24                       CHECK ! 

Let c = corn acres      cost = 45c

let  w = wheat acres =  2c (given)     cost = 60(2c) = 120c

let s = soybean acres = 1300 acres - corn acres - wheat acres = 1300 - c - 2c    cost = (50)(1300-3c)

All three of these costs added together = 69500 = 45c +120c + 50(1300-3c)     Now solve for 'c'

You should result in :

c = 300 acres

then

w = 2c = 600 acres

and

s = 1300 - corn - wheat = 1300 - 300 - 600 = 400 acres for wheat

There are ifinite answers to this ONE equation.  To find a DISCREET single solution for  c , w and s  you will need THREE equations relating the variables.....   Sorry!

There is a   +-  key on there somewhere...on the Web2.0 calculator it is between the  ' 0 ' and ' . ' keys....

When you take the 240th root of  11.4 / 3  while solving this you will get + or -   1.005578004      I susupect you forgot the negative possibility.....   Try that and you will see....

6-8b^2 = -202     subtract 6 from both sides of the equation to get

-8b^2 = -208       Now divide both sides by  - 8

b^2 = 26              Sq rt both sides

b = sqrt(26)  = 5.099

sqrt3/2 + sqrt3/2  =  2 (sqrt3 / 2)  = sqrt 3  = 1.732

Well,  cos(56) = .55919   so

.55919 = ab/72

or

72(.55919) = ab = 40.262