2007-03-25 20:43:42 · 12 answers · asked by BingBang 1 in Science & Mathematics ➔ Mathematics
12+9= -2a+5a (transposing)
21= 3a
21/3= 3a/3
answer is:
a= 7
2007-03-25 20:47:38 · answer #1 · answered by Anonymous · 0⤊ 0⤋
12- 5a = -2a - 9
12 + 9 = -2a + 5a
21 = 3a
7 = a
2007-03-25 22:39:58 · answer #2 · answered by crestfallen 5 · 0⤊ 0⤋
an trouble-free hint: once you progression something from left fringe of the "=" to precise side or vice versa, substitute the sign. ie. 12 on left side while pass to precise side turns into -12 Then the equation turns into: -2a = -5a -9 -12 in addition, being -5a to left side, then the equation turns into: -2a - (-5a) = -9 -12 -2a+5a = -21 3a = -21 a = -21/3 the respond..
2016-12-19 13:59:28 · answer #3 · answered by Anonymous · 0⤊ 0⤋
12 + 9 = - 2a + 5a
21 = 3a
a = 7
2007-03-25 20:48:31 · answer #4 · answered by Como 7 · 0⤊ 0⤋
12 - 5a = -2a - 9
12 + 9 = -2a + 5a
21 = 3a
a = 21/3
a = 7
2007-03-25 20:49:53 · answer #5 · answered by farina m 4 · 0⤊ 0⤋
5a + 2a = 12 + 9
7a = 21
therefore, a = 21/7 = 3
2007-03-25 20:49:07 · answer #6 · answered by flipper 2 · 0⤊ 0⤋
12-5a=2a-9 add 9 to both sides
21-5a=2a add 5a to both sides
21=7a divide both sides by 7
3=a
oops did not see the - in front of the 2a
12-5a = -2a-9 add 9 to both sides
21-5a= -2a add 5a to both sides
21=-2a+5a
21=3a divide both sides by 3
7=a
2007-03-25 20:48:45 · answer #7 · answered by J T 6 · 0⤊ 0⤋
12+9 = -2a + 5a
21 = 3a
a=7
2007-03-25 20:49:22 · answer #8 · answered by ........ 5 · 0⤊ 0⤋
First, add 2a to each side:
12-3a=-9
Now subtract 12 from each side:
-3a = -21
-a = -7
a = 7
2007-03-25 20:48:16 · answer #9 · answered by Jim S 5 · 0⤊ 0⤋
12-12-5a=-9-12-2a
-5a+2a=-21-2a+2a
-3a=-21
-3a/-3=-21/-3
a=7
2007-03-25 21:55:30 · answer #10 · answered by Dave aka Spider Monkey 7 · 0⤊ 0⤋