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方程组中的数量关系复杂,题型多变,现就其常见问题及其解法介绍如下.一、求方程中的字母系数例1 已知关于x,y的方程组 (a－b)x＋y=5, bx＋ay=6 x=1, y=2.的解是 求a,b的值. (a－b)×1＋2=5, b×1＋a×2=6. a=3, b=0.二、求代数式的值例2 已知2a3n－4bm＋2与a2m＋3b6－n是同类项,求(m－n)n的值. 3n－4=2m＋3, m＋2=6－n. m=1, n=3.
The quantity relationship in the equations is complex, and the types of questions are variable. Now we introduce the common problems and their solutions as follows. I. Find the letter coefficients in the equation Example 1 Known equations about x, y (a-b) x+y= 5, bx+ay=6 x=1, y=2. The solution is to find the value of a, b. (a-b)×1+2=5, b×1+a×2=6. a=3, b=0. , Algebraic Expressions Example 2 It is known that 2a3n-4bm+2 and a2m+3b6-n are similar terms and find the value of (m-n)n. 3n-4=2m+3, m+2=6-n. m=1, n=3.