Overview: 3 questions will be solved this time.Among them
           ☆1 equations
           ☆2 arithmetic calculations

[1/3 Formula]
    Work: Calculate the value of equation (-1+sqrt(1^2-4*1*(-4/9)))/2 .
    Question type: Mathematical calculation
    Solution:
          (-1+sqrt(1^2-4*1*(-4/9)))/2
        =(-1+sqrt(1^2-4*1*(-0.444444)))/2
        =(-1+sqrt2.777776)/2
        =0.666666/2
        =0.333333
    Answer:(-1+sqrt(1^2-4*1*(-4/9)))/2=0.333333
[2/3 Formula]
    Work: Calculate the value of equation (-1-sqrt(1^2-4*1*(-4/9)))/2 .
    Question type: Mathematical calculation
    Solution:
          (-1-sqrt(1^2-4*1*(-4/9)))/2
        =(-1-sqrt(1^2-4*1*(-0.444444)))/2
        =(-1-sqrt2.777776)/2
        =-2.666666/2
        =-1.333333
    Answer:(-1-sqrt(1^2-4*1*(-4/9)))/2=-1.333333
[ 3/3 Equation]
    Work: Find the solution of equation x^2+x-4/9 = 0 .
    Question type: Equation
    Solution:
    After the equation is converted into a general formula, it is converted into:
    ( 3x + 4 )( 3x - 1 )=0
    From
        3x + 4 = 0
        3x - 1 = 0
    it is concluded that:：

x1=

-

4 3

x2=

1 3

    
    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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