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current location:Mathematical operation > History of Inequality Computation > Answer
    Overview: 1 questions will be solved this time.Among them
           ☆1 equations

[ 1/1 Equation]
    Work: Find the solution of equation 50(1-0.3)(1+3x)×0.3(1-x) = 0 .
    Question type: Equation
    Solution:Original question:
     50(1
3
10
)(1 + 3 x ) ×
3
10
(1 x ) = 0
     Left side of the equation = 15(1
3
10
)(1 + 3 x )(1 x )
    The equation is transformed into :
     15(1
3
10
)(1 + 3 x )(1 x ) = 0
    Remove the bracket on the left of the equation:
     Left side of the equation = 15 × 1(1 + 3 x )(1 x )15 ×
3
10
(1 + 3 x )(1 x )
                                             = 15(1 + 3 x )(1 x )
9
2
(1 + 3 x )(1 x )
                                             = 15 × 1(1 x ) + 15 × 3 x (1 x )
9
2
(1 + 3 x )(1 x )
                                             = 15(1 x ) + 45 x (1 x )
9
2
(1 + 3 x )(1 x )
                                             = 15 × 115 x + 45 x (1 x )
9
2
(1 + 3 x )(1 x )
                                             = 1515 x + 45 x (1 x )
9
2
(1 + 3 x )(1 x )
                                             = 1515 x + 45 x × 145 x x
9
2
(1 + 3 x )(1 x )
                                             = 1515 x + 45 x 45 x x
9
2
(1 + 3 x )(1 x )
                                             = 15 + 30 x 45 x x
9
2
(1 + 3 x )(1 x )
                                             = 15 + 30 x 45 x x
9
2
× 1(1 x )
9
2
× 3 x
                                             = 15 + 30 x 45 x x
9
2
(1 x )
27
2
x (1 x )
                                             = 15 + 30 x 45 x x
9
2
× 1 +
9
2
x
27
2
x
                                             = 15 + 30 x 45 x x
9
2
+
9
2
x
27
2
x (1 x )
                                             =
21
2
+
69
2
x 45 x x
27
2
x (1 x )
                                             =
21
2
+
69
2
x 45 x x
27
2
x × 1 +
27
2
x x
                                             =
21
2
+
69
2
x 45 x x
27
2
x +
27
2
x x
                                             =
21
2
+ 21 x 45 x x +
27
2
x x
    The equation is transformed into :
     
21
2
+ 21 x 45 x x +
27
2
x x = 0

    After the equation is converted into a general formula, it is converted into:
    ( 3x + 1 )( x - 1 )=0
    From
        3x + 1 = 0
        x - 1 = 0

    it is concluded that::
        x1=-
1
3
        x2=1
    
    There are 2 solution(s).


解一元二次方程的详细方法请参阅:《一元二次方程的解法》




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