作业帮利用因式分解做几道计算题
来源：学生作业帮 编辑：作业帮 分类：数学作业 时间：2024/07/14 07:21:19
利用因式分解做几道计算题
1.(2x+y)的平方- (x+2y)的平方
2.(a-b)的平方+4ab
3.3.14乘以7.8的平方- 3.14乘以1.1的平方 乘以4
1.(2x+y)的平方- (x+2y)的平方
2.(a-b)的平方+4ab
3.3.14乘以7.8的平方- 3.14乘以1.1的平方 乘以4
(2x+y)的平方- (x+2y)的平方
=[(2x+y)- (x+2y)][(2x+y)+ (x+2y)]
=(x-y)(3x+3y)
=3(x-y)(x+y)
(a-b)^2+4ab
=a^2-2ab+b^2+4ab
=a^2+2ab+b^2
=(a+b)^2
3.14*7.8^2- 3.14*1.1^2*4
=3.14*7.8^2- 3.14*2.2^2
=3.14*(7.8^2- 2.2^2)
=3.14*(7.8+2.2)*(7.8-2.2)
=3.14*10*5.6
=31.4*5.6
=175.84
=[(2x+y)- (x+2y)][(2x+y)+ (x+2y)]
=(x-y)(3x+3y)
=3(x-y)(x+y)
(a-b)^2+4ab
=a^2-2ab+b^2+4ab
=a^2+2ab+b^2
=(a+b)^2
3.14*7.8^2- 3.14*1.1^2*4
=3.14*7.8^2- 3.14*2.2^2
=3.14*(7.8^2- 2.2^2)
=3.14*(7.8+2.2)*(7.8-2.2)
=3.14*10*5.6
=31.4*5.6
=175.84