同学们要注意培养利用整体思想进行解题的意识,下面就结合例题介绍整式的加减中几种重要的解题意识.意识一:“代”整体把已知条件中的式子作为一个整体,直接代入要求值的代数式中进行求值.例1若a+b=3,则(a+b)~2-5/(a+b)_a+b-2的值为____.思路点拨:由于要求值的代数式中含有字母的部分都有a+b,可以把a+b视为一个整体,直接代入求值. Students should pay attention to cultivate the use of the overall idea of ​​the problem-solving awareness, the following combination of examples to introduce the whole addition and subtraction in the sense of several important solutions. Consciousness: “generation ” as a whole the known conditions of the formula as (1) If a + b = 3, the value of (a + b) ~ 2-5 / (a ​​+ b) _a + b-2 is ____. Idea dial: As the algebraic value of the required part of the letter has a + b, you can treat a + b as a whole, directly into the evaluation.