2007-09-05 06:43:41 · 8 answers · asked by JacQuan E 1 in Science & Mathematics ➔ Mathematics
4/12x + 9/12 x = 13
13/12 x = 13
if x is in the numerator of your expression above, then...
x = 12
if denominator then...
x = 1/12
2007-09-05 06:49:08 · answer #1 · answered by Dr W 7 · 1⤊ 0⤋
Is that
(1/3)x + (3/4)x = 13
or
1 / (3x) + 3 / (4x) = 13??
********************
(1/3)x + (3/4)x = 13
common denominator is 12, so multiply everything by that.
12(1/3)x + 12(3/4)x = 12(13)
4x + 9x = 156
13x = 156
x = 12
*********************
1 / (3x) + 3 / (4x) = 13
Common denominator is 12x, so multiply everything by that.
(12x)(1 / 3x) + 12x(3/ 4x) = 12x(13)
4 + 9 = 156x
13 = 156x
13 / 156 = x
1 / 12 = x
2007-09-05 06:50:25 · answer #2 · answered by Mathematica 7 · 0⤊ 0⤋
1/3x+3/4x=13
Multiply by 12 getting
4x + 9x = 156
13x = 156
x = 156/13 = 12
2007-09-05 06:51:43 · answer #3 · answered by ironduke8159 7 · 0⤊ 0⤋
1/3x + 3/4x = 13
4/12x + 9/12x = 13
13/12x = 13
x = 12
Answer: x = 12
Proof:
1/3(12) + 3/4(12) = 13
4 + 9 = 13
2007-09-09 01:21:35 · answer #4 · answered by Jun Agruda 7 · 3⤊ 0⤋
The LCD (least common denominator) of 3 and 4 = 12 (3x4) so we put everyhing under denominator 12 :
4/12 x + 9/12 x = 13 => (13/12) x = 13 => x=12 !
2007-09-05 06:49:11 · answer #5 · answered by ?????? 7 · 0⤊ 0⤋
1/3x + 3/4x = 13.
4/12x + 9/12x = 13.
13/12x = 13.
x = 13 * (12/13).
x = 12.
2007-09-05 06:48:01 · answer #6 · answered by RustyL71 4 · 0⤊ 0⤋
4/12x+9/12x= 13/12x=13 x=12/13(13) x=12
2007-09-05 06:53:38 · answer #7 · answered by dwinbaycity 5 · 0⤊ 0⤋
Can't find the slash key on my calculator, sorry,
2007-09-05 06:54:14 · answer #8 · answered by Anonymous · 0⤊ 0⤋