2007-10-02 16:06:20 · 8 answers · asked by ciella r 1 in Science & Mathematics ➔ Mathematics
2n + 12 = 3n -31
12 + 31 = 3n - 2n
43 = n
2007-10-02 16:11:21 · answer #1 · answered by ecolink 7 · 1⤊ 0⤋
Let the number be x.
2x + 12 = 3x - 31
Let's flip the equation to make it simpler:
3x - 31 = 2x + 12
Bring all the x to the left and all the numbers to the left.
3x - 2x = 12 + 31
x = 43
Let's check:
Twice a number = 2x = 2 * 43 = 86
Three times a number = 3x = 3 * 43 = 129
86 + 12 = 98
129 - 98 = 31 (Correct)
So the number in question is 43.
2007-10-02 16:25:21 · answer #2 · answered by Steven Prasetya 2 · 0⤊ 0⤋
let x = the number
2x + 12 = 3x - 31
x = 12 + 31 = 43
2007-10-02 16:15:09 · answer #3 · answered by vlee1225 6 · 0⤊ 0⤋
The equation would be 2X + 12 = 3X -31. (Whenever there is an "is" that means equals. Just make whatever "the number" is be X and go thru it slowly to write the equation.) Once you have that, just solve for X. X=43. The number is 43. You can then plug it in and check if it's right. It is right :) Good luck :)
2007-10-02 16:13:33 · answer #4 · answered by Midgesauce 2 · 0⤊ 0⤋
2x + 12 = 3x - 31
2x - 3x = -12 -31
-x = -43
x = 43
2007-10-02 16:18:39 · answer #5 · answered by Monkichi 2 · 0⤊ 0⤋
2x + 12 = 3x - 31
-x = -45
x = 45
2007-10-02 16:12:56 · answer #6 · answered by Seto 2 · 0⤊ 1⤋
let the no. be A
2A+12 = 3A-31
12+31 = 3A-2A
A = 43
2007-10-02 16:13:01 · answer #7 · answered by Anonymous · 0⤊ 0⤋
it is 7 i think
2007-10-02 16:18:24 · answer #8 · answered by danny 2 · 0⤊ 0⤋