4.代数式的值的求法学会求代数式的值是很有用的. 求代数式的值的方法很丰富多采,往往是因题而异. 求代数式的值,最基本的方法是(1)直接代入字母的值例1 已知a=-4/5,求代数式3a3-(a+a3-2a2-2)-2(1+a2+a3-6a)的值. 解当a=-4/5时,所给代数式的值是 4. The algebraic expression of the value of the law to learn algebraic expressions of the value is very useful. Algebraic expressions of the value of the method is very rich and varied, often vary from question to question. The algebraic expression of the value, the most basic method is (1) direct substitution The value of the letter 1 is known as a=-4/5 and the algebraic expression 3a3-(a+a3-2a2-2)-2(1+a2+a3-6a) is calculated. When the solution is a=-4/5 , the algebraic value given is