how do you solve the equation 12x^2+3x=0?

2009-11-27 2:34 pm
please help!!
i need the answer noww!!
i cant do my hw :(

回答 (6)

2009-11-27 2:43 pm
✔ 最佳答案
12x^2 + 3x = 0
3x(4x) + 3x(1) = 0
3x(4x + 1) = 0

3x = 0
x = 0/3
x = 0

4x + 1 = 0
4x = -1
x = -1/4 (-0.25)

∴ x = -1/4 (-0.25), 0
2009-11-27 2:37 pm
Factor
3x(4x + 1) = 0
==> x = 0 or x = -1/4
參考: retired math teacher
2009-11-30 6:42 pm
3x ( 4x + 1 ) = 0

x = 0 , x = - 1/4
2009-11-30 2:51 pm
12x^2+3x=0

3x(4x+1)=0

x=0 or -1/4
2009-11-27 2:51 pm
stick the coefficients into te quadratic formula and see what you get :

a=12
b=3
c=0

thus
x = {-3 +/- [(3)^2 - 4(12)(0)]^(1/2)} / 2(12)
= {-3 +/- 3 } / 24
= 0 , -6/24
= 0, -1/4
2009-11-27 2:38 pm
factor out the 3x
3x(4x+1)=0 divide the 3x out
4x+1=0 one of the x's equals 0
4x=-1
x=-1/4

x=-1/4 and 0


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