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2012年中考中,涉及一元一次方程的考点有哪些呢?请辛老师来告诉大家吧.一、方程的解例1(2012年重庆)已知关于x的方程2x+a-9=0的解是x=2,则a的值为().A.2 B.3 C.4 D.5解析:根据方程的解的定义,把x=2代入方程,解关于a的一元一次方程即可.把x=2代入方程得2×2+a-9=0,解得a=5.故选D.二、列方程例2(2012年铜仁)铜仁市对城区主干道进行绿化,计划把某一段公路的一侧全部栽上桂花树,要求路的两端各栽1棵,并且每2棵树的间隔相等.如果每隔5米栽1棵,则
In the middle school entrance examination in 2012, involving a unitary equation of the test center what? Please Xin teacher to tell you.A solution of the equation 1 (2012 in Chongqing) known on the x equation 2x + a-9 = 0 solution Is x = 2, the value of a is () .A.2 B.3 C.4 D.5 Resolution: According to the definition of the solution of the equation, substitute x = 2 into the equation and solve the unary equation of a . Substitute x = 2 into the equation to get 2 × 2 + a-9 = 0 and solve for a = 5. Therefore, D. Second, column equation Example 2 (Tongren 2012) Tongren City, One side of a section of the road planted all the sweet-scented osmanthus trees, requiring two ends of the road planted a tree, and every two trees equally spaced if planted every 5 meters, then