Question

（8-x）(6-x)/2=12

Answer 1

解： (x-4）/ (x-5) - (x-5)/(x-6) = (x-7) / (x-8) - (x-8) / (x-9) 对方程两边各自通分： [(x-4)(x-6) - (x-5)(x-5)] / [(x-5)/(x-6)] = [(x-7)(x-9) - (x-8)(x-8)] / [(x-8)(x-9)] (x^2-10x+24-x^2+10x-25) / [(x-5)/(x-6)] = [x^2-16x+63 - x^2+16x-64] / [(x-8)(x-9)] 1 / [(x-5)/(x-6)] = 1 / [(x-8)(x-9)] 所以： (x-5)(x-6)=(x-8)(x-9) x^2-11x+30=x^2-17x+72 6x=42 x=7 带入原方程：左边=-1/2 右边=-1/2 左边=右边 ∴x=7是原方程的解

Answer 2

red