2007-06-27 18:22:20 · 4 answers · asked by Kristina D 1 in Science & Mathematics ➔ Mathematics
|3x + 4 - 25| = |3x - 21| = |3(x - 7)| = 3|x - 7| < 0.2 <=> |x - 7|<0.2/3 = 2/30. So, we have to take x within a distance of 2/30 = 0.0666... from 7, that is, x must be in the interval (6.9333...
, 7.0666...)
2007-06-27 19:04:55 · answer #1 · answered by Steiner 7 · 0⤊ 1⤋
If w is within a distance of c units from b, then | w - b | < c.
| (3x + 4) - 25 | < 0.2
| 3x - 21 | < 0.2
| 3(x - 7) | < 0.2
| 3 | * | x - 7 | < 0.2
3| x - 7 | < 0.2
divide both sides by 3
| x - 7 | < 1 / 15
Answer: x is within 1/15 of a unit of 7.
2007-06-28 01:48:08 · answer #2 · answered by mathjoe 3 · 0⤊ 0⤋
3x + 4 = 25 - .2
3x + 4 = 24.8
3x + 4 - 4 = 24.8 - 4
3x = 20.8
3x/3 = 20.8/3
x = 6.9333
x = 6.93
and
3x + 4 = 25 + .2
3x + 4 = 25.2
3x + 4 - 4 = 25.2 - 4
3x = 21.2
3x/3 = 21.2/3
x = 7.0666
x = 7.07
2007-06-28 01:31:28 · answer #3 · answered by detektibgapo 5 · 0⤊ 0⤋
3x+4=24.8
3x=20.8
x=(20.8/)3
x=6.933333...
AND
3x+4=25.2
3x=21.2
x=(21.2)/3
x=7.06666...
2007-06-28 01:27:36 · answer #4 · answered by Avi R 2 · 0⤊ 0⤋