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On line Solution of Monovariate Equation：
    Input any unary equation directly, and then click the "Next" button to obtain the solution of the equation.
    It supports equations that contain mathematical functions.
    Current location：Equations > Monovariate Equation > The history of univariate equation calculation > Answer
    Overview: 1 questions will be solved this time.Among them
           ☆1 equations

[ 1/1 Equation]
    Work: Find the solution of equation 2（21+x）（15+2x）+15+2x = 875 .
    Question type: Equation
    Solution:Original question:
     2(21 + x )(15 + 2 x ) + 15 + 2 x = 875
    Remove the bracket on the left of the equation:
     Left side of the equation = 2 × 21(15 + 2 x ) + 2 x (15 + 2 x ) + 15 + 2 x
                                             = 42(15 + 2 x ) + 2 x (15 + 2 x ) + 15 + 2 x
                                             = 42 × 15 + 42 × 2 x + 2 x (15 + 2 x ) + 15 + 2 x
                                             = 630 + 84 x + 2 x (15 + 2 x ) + 15 + 2 x
                                             = 645 + 86 x + 2 x (15 + 2 x )
                                             = 645 + 86 x + 2 x × 15 + 2 x × 2 x
                                             = 645 + 86 x + 30 x + 4 x x
                                             = 645 + 116 x + 4 x x
    The equation is transformed into :
     645 + 116 x + 4 x x = 875

    The solution of the equation:
        x1≈-30.863068 , keep 6 decimal places
        x2≈1.863068 , keep 6 decimal places    
    There are 2 solution(s).

解程的详细方法请参阅：《方程的解法》


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