3(x-5)+3x=4x+5
3x-15+3x=4x+5
-15x=4x+5
4x=-20x
x=-5
2007-07-20 15:31:35 · 7 answers · asked by LiberT 1 in Science & Mathematics ➔ Mathematics
3(x-5)+3x=4x+5
3x-15+3x=4x+5
here is where you went wrong, it should be
6x - 15 = 4x + 5
2x - 15 = 5
2x = 20
x = 10
2007-07-20 15:35:28 · answer #1 · answered by N E 7 · 0⤊ 0⤋
If we substitute x = -5 we get
3(-5-5) + 3(-5) = 4(-5) + 5
3(-10) -15 = -20 + 5
-30 - 15 = -15 ----> this is wrong hence x = -5 is not a solution.
The actual steps are:
3(x-5)+3x=4x+5 --- (1)
3x-15+3x=4x+5
=> 6x - 15 = 4x + 5
=> 6x - 4x = 15 + 5
=> 2x = 20
=> x = 10.
Substituting x = 10 in (1) we get,
3(10 - 5) + 3*10 = 4*10 + 5
=> 3*5 + 30 = 40 + 5
=> 15+30 = 45
=> 45 = 45 ---- therefore x = 10 is correct.
2007-07-20 22:39:06 · answer #2 · answered by ping_anand 3 · 0⤊ 0⤋
these are the possible answer to your question????
3(x-5)+3x=4x+5
3x-15+3x=4x+5
here is where you went wrong, it should be
6x - 15 = 4x + 5
2x - 15 = 5
2x = 20
x = 10
You made a mistake once you reached your third step;
It should read,
6x-15=4x+5
2x-15=5
2x=20
x=10
3(x-5)+3x=4x+5
3x-15+3x=4x+5 that's good
But now you've gone wrong
-15x=4x+5
this should be 6x-15 =4x+5
so, 2x =20
x=10
If we substitute x = -5 we get
3(-5-5) + 3(-5) = 4(-5) + 5
3(-10) -15 = -20 + 5
-30 - 15 = -15 ----> this is wrong hence x = -5 is not a solution.
The actual steps are:
3(x-5)+3x=4x+5 --- (1)
3x-15+3x=4x+5
=> 6x - 15 = 4x + 5
2007-07-20 23:03:14 · answer #3 · answered by jhon 2 · 0⤊ 0⤋
3(x - 5) + 3x = 4x + 5
3x - 15 + 3x = 4x + 5
6x - 15 = 4x + 5
6x - 4x = 5 + 15
2x = 20
x = 20/2
x = 10
2007-07-20 23:13:48 · answer #4 · answered by Jun Agruda 7 · 2⤊ 0⤋
6x -15=4x+5
6x - 4x = 5 + 15
2x = 20
x=10
demostration:
3(10-5) + 3(10) = 4(10)+5
3(5) + 30 = 40 + 5
15 + 30 = 45
45 = 45
2007-07-20 22:42:12 · answer #5 · answered by Jorge MEX 6 · 0⤊ 0⤋
3(x-5)+3x=4x+5
3x-15+3x=4x+5 that's good
But now you've gone wrong
-15x=4x+5
this should be 6x-15 =4x+5
so, 2x =20
x=10
2007-07-20 22:38:20 · answer #6 · answered by Anonymous · 0⤊ 0⤋
You made a mistake once you reached your third step;
It should read,
6x-15=4x+5
2x-15=5
2x=20
x=10
2007-07-20 22:36:44 · answer #7 · answered by Anonymous · 0⤊ 0⤋