Sandeep's Responses in WyzAnt Answers

it seems like your question in not complete , please check & repost your problem.

2x+7 < X-4

substract x from both sides

2X+7 -X < X-4-X

or  X+7 < -4

now substract 7 from both sides

X+7-7 < -4-7

or X < -11

 answer is ( infinity, -11)

2x+5y = 14   ---equation 1

3x-2y= -36  ----equation 2 

multiply eq. 1 by (-3) and eq.2 by 2 and add the two equations- 

-6x - 15 y = -42 

6x-4y       = -72 

_________________

-19y =- 114

y = 6 

2x + 5*6 = 14 

2x = 14-30 = 16

x = -8 

You have 4 cells with frequescise in your problem - 

95 , 25, 105 , 275 

best way to do this problem is make  2X2 table and put observed and expected frequencies in the table. 

as explained above to calculate expected frequency you will take row total & column total & devide by grand total for each cell.

so for 95 - Exp freq = (120*200/500) = 48

for     25 - Exp freq = ( 120*300/500) = 72

for    105 Exp Freq  = ( 380*200/500) =  152 

for    275   Exp Freq = ( 275*300/500) = 228

Now calculate this for each cell  (Observed - Expected) ^2/ Expected and add them - 

( 95-48)^2/48 + (25-72)^2/72 + ( 105-152)^2/152  + ( 275-228)^2/ 228 = 46.02 + 30.68 + 14.53 + 0.69 = 100.9

degrees of freedom = (# of rows -1 ) ( # of columns-1) = ( 2-1)(2-1) = 1 

let me know if you have any questions or you don't understand anything.