Question

解方程1、(2x+3)(2x-5)-(2x+1)^2=40 2、 5(x^2-3)-4x(6+x)+x(-x+4)=0

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Answer 1

1. 原式=4x^2+6x-10x-15-4x^2-4x-1=40
   

   -8x-16=40

   x=-7

2. 5x^2-15-24x-4x^2-x^2+4x=0

   -15=20x

   x=-3/4
   

Answer 2

1. -4x-4x-15-1=40 x=3

2. -15-24x+4x=0 x=-3/4