SOLUTION: solve the proper pH of the water in swimming pools is 7.4 + or - 0.2. Write an absolute value inequality representing this range. Then solve the inequality to state the range of

Question 997727: solve
the proper pH of the water in swimming pools is 7.4 + or - 0.2. Write an absolute value inequality representing this range. Then solve the inequality to state the range of the pH.
Answer by Theo(13342) (Show Source): You can put this solution on YOUR website!
let x represent the ph of the water.

|x - 7.4| <= .2

when (x - 7.4) is positve, the equation becomes (x - 7.4) <= .2 which results in x <= 7.6

when (x - 7.4) is negative, the equation becomes (x - 7.4) >= -.2 which results in x >= 7.2

you reverse the inequality and you change the sign of the expression on the right when (x - 7.4) is negative.

there's a valid reason for doing this that i won't get into unless you ask.
it involves the basic definition of absolute value.

you get x <= 7.6 and x >= 7.4.

this can be written as 7.4 <= x <= 7.6

this means that the ph is good if it reads from 7.4 to 7.6 and not good otherwise.

RELATED QUESTIONS
solve and graph the absolute value inequality, write the solution in interval notation (answered by Fombitz)

My question is: Cucumbers grow in soil having a ph level of 6.5, with a tolerance of 1 (answered by jim_thompson5910)

Solve the inequality involving absolute value. Write your final answer in interval... (answered by Boreal)

Write an absolute value equation representing the following; then solve the equation... (answered by josgarithmetic)

Write an absolute value equation representing the following; then solve the equation:... (answered by Boreal)

The ph of a slution ranges from 0 to 14. An acid has a ph less than 7. Pure water is... (answered by Earlsdon)

solve An investor has decided to sell his shares of stock in the stock's price... (answered by Theo)

Solve Meat should be stored below 40 degrees F or kept above 140 degrees F after... (answered by Theo)

I am having problems figuring out what the absolute value is for this problem: Solve by... (answered by stanbon)