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在整式的计算、化简、求值中,若能正确、灵活地运用法则、公式,并且掌握某些运算技巧,就能使代数运算变得十分简洁.下面归纳、总结整式乘法运算的几种常用技巧,供同学们学习时参考.一适当变形,运用公式例1化简:(x+2y-3z)(x-2y+3z).分析:两个含有三项的多项式相乘,需相乘9次,再合并同类项,这是一项多么麻烦的计算!现在我们来观察因式(x+2y-3z)、(x-2y+3z),不难发现2y-3z和-2y+3z互为相反数,于是想到将x-2y+3z变形为x-(2y-3z),从而便可以运用平方差公式来计算.
In the integral calculation, simplification, evaluation, if the correct and flexible use of rules, formulas, and master some arithmetic skills, can make the algebraic operation becomes very simple. Summarize, summarize the integer multiplication operation Commonly used skills for students to learn when reference. An appropriate deformation, using the formula Example 1 simplification: (x +2 y-3z) (x-2y +3 z). Analysis: two polynomials containing three multiplication, phase By multiplying 9 times and then merging the same items, what a hassle calculation! Now let’s look at the factors (x + 2y-3z), (x-2y + 3z) and find that 2y-3z and -2y + 3z each other the opposite, then think of x-2y + 3z transformed into x- (2y-3z), which can be calculated using the square deviation formula.