(2a+3b)^2-(3a-2b)^2 =[(2a+3b)+(3a-2b)][(2a+3b)-(3a-2b)] ① =(5a+b)(5b-a) ② =25ab-5a^2+5b^2-ab ③ =5b^2+24ab-5a^2 ④ (1)上述计算过程中第①步的根据是________________; 第②步是_____________________运算; 第③步是____
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![(2a+3b)^2-(3a-2b)^2 =[(2a+3b)+(3a-2b)][(2a+3b)-(3a-2b)] ① =(5a+b)(5b-a) ② =25ab-5a^2+5b^2-ab ③ =5b^2+24ab-5a^2 ④ (1)上述计算过程中第①步的根据是________________; 第②步是_____________________运算; 第③步是____](/uploads/image/z/1268010-18-0.jpg?t=%282a%2B3b%29%5E2-%283a-2b%29%5E2++%3D%5B%282a%2B3b%29%2B%283a-2b%29%5D%5B%282a%2B3b%29-%283a-2b%29%5D+%E2%91%A0+%3D%285a%2Bb%29%285b-a%29+%E2%91%A1+%3D25ab-5a%5E2%2B5b%5E2-ab+%E2%91%A2+%3D5b%5E2%2B24ab-5a%5E2+%E2%91%A3+%EF%BC%881%EF%BC%89%E4%B8%8A%E8%BF%B0%E8%AE%A1%E7%AE%97%E8%BF%87%E7%A8%8B%E4%B8%AD%E7%AC%AC%E2%91%A0%E6%AD%A5%E7%9A%84%E6%A0%B9%E6%8D%AE%E6%98%AF________________%EF%BC%9B+%E7%AC%AC%E2%91%A1%E6%AD%A5%E6%98%AF_____________________%E8%BF%90%E7%AE%97%EF%BC%9B+%E7%AC%AC%E2%91%A2%E6%AD%A5%E6%98%AF____)
(2a+3b)^2-(3a-2b)^2 =[(2a+3b)+(3a-2b)][(2a+3b)-(3a-2b)] ① =(5a+b)(5b-a) ② =25ab-5a^2+5b^2-ab ③ =5b^2+24ab-5a^2 ④ (1)上述计算过程中第①步的根据是________________; 第②步是_____________________运算; 第③步是____
(2a+3b)^2-(3a-2b)^2 =[(2a+3b)+(3a-2b)][(2a+3b)-(3a-2b)] ① =(5a+b)(5b-a) ② =25ab-5a^2+5b^2-ab ③ =5b^2+24ab-5a^2 ④ (1)上述计算过程中第①步的根据是________________; 第②步是_____________________运算; 第③步是_____________________运算. (2)仿照上述方法计算(x+y-z)^2-(x-y+z)^2
(2a+3b)^2-(3a-2b)^2 =[(2a+3b)+(3a-2b)][(2a+3b)-(3a-2b)] ① =(5a+b)(5b-a) ② =25ab-5a^2+5b^2-ab ③ =5b^2+24ab-5a^2 ④ (1)上述计算过程中第①步的根据是________________; 第②步是_____________________运算; 第③步是____
1、平方差公式 2、合并同类型(即 乘法分配律) 3、因式分解(不过我们这种教材上没有这种因式分解.没见过 4、(x+y-z)^2-(x-y+z)^2 =(x+y-z+x-y+z)【x+y-z-(x-y+z)】 =x*(2y-2z) =2xy-2xz