6x - 12 = 2x + 8
6x - 2x = 8 + 12
4x = 20
x = 5
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Larry K. say: Yasmin, Andy's right but since you've asked how you do this let me elaborate on what Andy did. First, you must realize that the equals sign means that one side of the equation equals the other side. If I were to write
6 - 3 = 12 - 9 you could do the math and you'd get 3 = 3. Solving algebra equations is really very similar. Look at the equation first.
3(2x - 4) = 2x + 8.......If you do the expansion of the left side first you get
6x - 12 = 2x + 8.......Okay, to get rid of the 2x on the right, subtract 2x from both sides (remember, that doing this still keeps the sides equal). this comes out to be: 4x - 12 = 8......Okay, now add 12 to each side (to get rid of the minus 12 on the left). This gives you 4x = 20. Finally, to just get x on the left, divide each side by 4, this leaves you with x = 5. Do you see? We've kept the sides equal by doing the same thing to each side. Finally, if you wish to check your answer, replace 5 for x in the equation and see if it works.
3[(2 x 5) - 12] = 2(5) +8.......you get 3 (10) - 12 = 10 + 8 or 30 - 12 = 18
So 18 = 18 and it must be right. I hope this helps. It's really pretty simple if you just remember to do the same thing to each side of the equals sign.
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Krishnamurthy say: 3(2x - 4) = 2x + 8
4x = 20
x = 5
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Colin say: Multiply the left side out.
6*x -12 = 2*x + 8
Subtract 2*x from both sides.
Add 12 to both sides.
Divide both sides by the number in front of the x.
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Andrew say: If you're trying to find x, then
3(2x-4) = 2x+8
6x-12 = 2x+8
6x-2x = 8+12
4x = 20
X = 20/4
X = 5
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