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

[ 1/1 Equation]
    Work: Find the solution of equation (x-20-1)(40-2x) = 300 .
    Question type: Equation
    Solution:Original question:
     ( x − 20 − 1)(40 − 2 x ) = 300
    Remove the bracket on the left of the equation:
     Left side of the equation = x (40 − 2 x ) − 20(40 − 2 x ) − 1(40 − 2 x )
                                             = x × 40 − x × 2 x − 20(40 − 2 x ) − 1(40 − 2 x )
                                             = 40 x − x × 2 x − 20 × 40 + 20 × 2 x − 1(40 − 2 x )
                                             = 40 x − x × 2 x − 800 + 40 x − 1(40 − 2 x )
                                             = 80 x − x × 2 x − 800 − 1(40 − 2 x )
                                             = 80 x − x × 2 x − 800 − 1 × 40 + 1 × 2 x
                                             = 80 x − x × 2 x − 800 − 40 + 2 x
                                             = 82 x − x × 2 x − 840
    The equation is transformed into :
     82 x − x × 2 x − 840 = 300
    This equation has no real solution!


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