Soil acidity is measured by a quantity called the ph, which may range from 0 to 14 for soils ranging from extreme alkalinity to extreme acidity. many soils have an average ph in the more-or-less- neutral 5 to 8 range. a scientist wants to estimate the average ph for a large field from n randomly selected core samples, measuring the ph of each sample. from experience he expects the standard deviation of the measurements to be 0.5. if the scientist selects n = 40 samples, find the approximate probability that the sample mean of the 40 ph measurements will be within 0.2 of the true average ph for the field.

{x = -1/2 ,   y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer:   {x = -1/2 ,   y = -1

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a

step-by-step explanation:

answer: you need to organize this better it does not make sense.

step-by-step explanation: ?