Solving Linear Equations
2006-09-13 14:44:50 · 21 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
3x-12 =9 u need to isolate the x
3x = 21
x = 7
yes, im the first one
yahoo!!!!!!!!!!!!
2006-09-13 14:46:26 · answer #1 · answered by Anonymous · 0⤊ 1⤋
Ok...this equation is quite simple
3x - 12 = 9
add 12 to each side of the equation
3x = 9 + 12 = 21
x = 21/3
x = 7
The key step is to recognize that you need to add 12 to both sides of the equation.
Good luck.
2006-09-13 14:48:24 · answer #2 · answered by alrivera_1 4 · 0⤊ 0⤋
Add 12 to 9, then you have 3x = 21
Divide both sides by 3 and you have x = 7
2006-09-13 14:47:10 · answer #3 · answered by kustramo 1 · 0⤊ 0⤋
3x-12=9
+12 to both sides
3x=21
divde by 3 to both sides
x=7
2006-09-13 14:53:59 · answer #4 · answered by yellowskinnedguy 3 · 0⤊ 0⤋
x = 7
2006-09-13 14:48:11 · answer #5 · answered by Anonymous · 0⤊ 0⤋
3x-12=9
First move the 12 to the other side of the equals sign by applying +12 to each side of the equals.
3x-12 (+12) = 9 (+12)
[since -12+12 = 0 they cancel each other]
3x=9+12
which gives;
3x=21
Now we move the 3 to the other side of equals
by dividing both sides by three...
(3÷3)x=21 (÷ 3)
which becomes;
x=21 ÷ 3
solve for x;
x=7
2006-09-13 15:06:56 · answer #6 · answered by Michael Darnell 7 · 0⤊ 0⤋
3x - 12 = 9
3x = 9 + 12
3x = 21
x = 21 / 3
x = 07
2006-09-13 14:53:35 · answer #7 · answered by bhavishyathi 3 · 0⤊ 0⤋
3x-12=9
add 12 to both sides
3x-12+12=9+12
3x=21
the divide by three to leave the x on one side
3x/3=21/3
you are left with
x=7
2006-09-13 15:17:33 · answer #8 · answered by rollandday 2 · 0⤊ 0⤋
3X - 12 = 9
3X = 9 + 12
3X = 21
X = 21/3
X = 7
2006-09-13 14:52:49 · answer #9 · answered by FrogDog 4 · 0⤊ 0⤋
You want to isolate that variable. So add 12 to both sides. This gives you 3x=21. Then to isolate x further, divide both sides by three. That will give you the answer.
2006-09-13 14:52:51 · answer #10 · answered by weebat 3 · 0⤊ 0⤋
3x=12+9
3x=21
x=7
2006-09-13 14:52:27 · answer #11 · answered by Chris E 3 · 0⤊ 0⤋