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math help?
3x2 -12x = 9
solve for x? I don't know what to do when there are two x's in the equation. I'm doing summer review so math will be easier when school starts.
3 Answers
- AshLv 77 years agoFavorite Answer
The x have different powers. This is quadratic equation. So we find factors.
3x² - 12x = 9
3x² - 12x -9 = 0
x² - 4x - 3 = 0
Use quadratic formula
x = [-(-4)±√(-4)²-4(1)(-3)] / 2(1)
x = (4±√28)/2
x = 2 ± √7
- 7 years ago
the first x is multiplication. 3*2 = 6
the second is a variable, so really there's only one x. Does that answer the question?
- 7 years ago
3x² - 12x = 9
=>3x² - 12x -9 = 0
=>3(x² - 4x - 3) = 0
=>x² - 4x - 3 = 0
=>(x-2)²-7=0
=>(x-2)²=7
=>x= 2 ± √7
