How to solve problem 5|3x-3|-4=19?

2008-07-17 11:35 am

回答 (12)

2008-07-17 11:44 am
✔ 最佳答案
5|3x-3|-4=19
if 3x-3<0=>x<1 then
-15x+15-4=19
-15x=8
x = -8/15
==> (-8/15,1)
if 3x-3>0=>x>1 then
15x-15-4=19
15x=38
x=38/15
==>(1,38/15)

so the solution is (-8/15,1)U(1,38/15)
2008-07-17 10:35 pm
5|3x - 3| - 4 = 19
5|3x - 3| = 19 + 4
5|3x - 3| = 23
|3x - 3| = 23/5
3x - 3 = ±23/5

3x - 3 = 23/5
3x = 23/5 + 3
3x = 23/5 + 15/5
3x = 38/5
x = (38/5)/3
x = 38/15

3x - 3 = -23/5
3x = -23/5 + 3
3x = -23/5 + 15/5
3x = -8/5
x = (-8/5)/3
x = -8/15

∴ x = -8/15 , 38/15
2008-07-17 7:15 pm
give a points when the answer is correct..

5|3x-3|-4=19
15x-15-4=19
15x=19+15+4
x=38/15

the answer is x=2.53
2008-07-17 7:06 pm
5 | 3x - 3 | = 23
| 3x - 3 | = 23/5

3x - 3 = 23/5
3x = 38/5
x = 38/15

3x - 3 = - 23/5
3x = - 8/5
x = - 8/15

x = 38/15 , x = - 8/15
2008-07-17 6:49 pm
5|3x-3|-4=19
5|3x-3|=19+4
5|3x-3|=23
|3x-3|=23/5

since its absolute value, you will have 2 equations. first

3x-3 = 23/5
3x = 23/5 + 3
3x = (23+15)/5
3x=38/5

x = 38/15 (first answer)

Second,
3x-3 = -23/5
3x = -23/5 + 3
3x = (-23+15)/5
3x = -8/5
x = -8/15 (2nd answer)

Answers: 38/15 and -8/15
2008-07-17 6:48 pm
5|3x-3|-4=19
5|3x-3| = 23
|3x-3| = 23/5
3x-3 =23/5 or 3x -3 = -23/5 [since |23/5or -23/5| = 23/5]
3x= 7.6 or 3x = -1.6
x = 2.53 or x = -0.53
2008-07-17 6:47 pm
5|3x-3|-4=19
5|3x-3|=19+4
|3x-3|=(19+4)/5
3x-3=√[(19+4)/5]^2
3x=√[(19+4)/5]^2+3
x={√[(19+4)/5]^2+3}/3 ---->this is technically solved for 'x', but if your teacher is stingy you'll need to simplify, so...
x=[√(23/5)^2+3]/3
x=(23/5+3)/3 or x=(-23/5+3)/3
x=(38/5)/3 or x=(-8/5)/3
x= 38/15 or x=-8/15

(keep in mind, it's 'OR', not 'AND')
參考: my way is best :P
2008-07-17 6:45 pm
5!3x-3!-4=19
15x-15-4=19
15x-19=19
15x=19+19
15x=38
x=38/15
2008-07-17 6:44 pm
5|3x-3|-4=19
5|3x-3|=23
|3x-3|=23/5

3x-3=23/5 or 3x-3=-23/5
3x=(23/5)+3 or 3x=-(23/5)+3

From there expand the brackets and then divide through by 3 and you get your two results for x which are 2.533 and -1.6
2008-07-17 6:43 pm
5(3x-3)-4=19
15x-15-4=19
15x=19+15+4
15x=38
15x/15=38/15
x=38/15


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