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Question 5268: I need help with some Pre-Algebra Eqautions
1. 3x - 5 - 2x = 8 - 9
2. 8x + 7 - 7x + 2 = -3
3. 3x + 4x + 9 = 2(x - 3)
PLEASE, PLEASE, PLEASE HELP1
Found 2 solutions by ichudov, AnlytcPhil: Answer by ichudov(507) (Show Source): Answer by AnlytcPhil(1806) (Show Source):
You can put this solution on YOUR website! 1. 3x - 5 - 2x = 8 - 9
3x - 5 - 2x = 8 - 9
Combine the 3x and the -2x getting x
x - 5 = 8 - 9
Combine the 8 and -9, getting -1
x - 5 = -1
Add 5 to both sides
x - 5 + 5 = -1 + 5
Combine the -5 and +5 getting 0
x + 0 = -1 + 5
Combine the x and the 0, getting just x
x = -1 + 5
Combine the -1 and the 5, getting 4
x = 4
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2. 8x + 7 - 7x + 2 = -3
8x + 7 - 7x + 2 = -3
Combine the 8x and the -7x, getting 1x, or x
x + 7 + 2 = -3
Combine the +7 and the +2, getting +9
x + 9 = -3
Subtract 9 from both sides
x + 9 - 9 = -3 - 9
Combine the 9 and the -9, getting 0
x + 0 = -3 - 9
Combine the x and the 0, getting x
x = -3 - 9
Combine the -3 and the -9, getting -12
x = -1
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3. 3x + 4x + 9 = 2(x - 3)
3x + 4x + 9 = 2(x - 3)
Combine the 3x and the 4x, getting 7x
7x + 9 = 2(x - 3)
Use the distributive principle to remove the parentheses
on the right, that is, multiply 2 by each of the terms
x and -3 inside the parentheses
7x + 9 = 2x - 6
Subtract 9 from both sides:
7x + 9 - 9 = 2x - 6 - 9
Combine the + 9 and the -9, getting 0
7x + 0 = 2x - 6 - 9
Combine the 7x and the 0, getting 7x
7x = 2x - 6 - 9
Combine the -6 and the -9, getting -15
7x = 2x - 15
Subtract 2x from both sides:
7x - 2x = 2x - 15 - 2x
Combine the 7x and the -2x, getting 5x
5x = 2x - 15 - 2x
Combine the 2x and the -2x, getting 0
5x = 0 - 15
Combine the 0 and the -15, getting -15
5x = -15
Divide both sides by the coefficient of x, which is 5,
getting x on the left side and -3 on the right side
x = -3
Edwin
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