已知a+b=3,则a²-b²+6b的值为多少?速求答案,要有过程,谢谢!
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/23 14:26:34
![已知a+b=3,则a²-b²+6b的值为多少?速求答案,要有过程,谢谢!](/uploads/image/z/437417-17-7.jpg?t=%E5%B7%B2%E7%9F%A5a%2Bb%3D3%2C%E5%88%99a%26%23178%3B-b%26%23178%3B%2B6b%E7%9A%84%E5%80%BC%E4%B8%BA%E5%A4%9A%E5%B0%91%3F%E9%80%9F%E6%B1%82%E7%AD%94%E6%A1%88%2C%E8%A6%81%E6%9C%89%E8%BF%87%E7%A8%8B%2C%E8%B0%A2%E8%B0%A2%21)
已知a+b=3,则a²-b²+6b的值为多少?速求答案,要有过程,谢谢!
已知a+b=3,则a²-b²+6b的值为多少?
速求答案,要有过程,谢谢!
已知a+b=3,则a²-b²+6b的值为多少?速求答案,要有过程,谢谢!
a²-b²+6b
=(a+b)(a-b)+6b
=3(a-b)+6b
=3a-3b+6b
=3a+3b
=3(a+b)
=9
a²-b²+6b
=(a+b)(a-b)+6b
=3(a-b)+6b
=3a+3b
=3(a+b)
=9
【】
a+b=3
a²-b²+6b
=(a-b)(a+b)+6b
=3(a-b)+6b
=3a+3b
=9
a=3-b
带入a²-b²+6b中得:(3-b)²-b²+6b=9-6b+b²-b²+6b=9
什么意思?
a=3-b
a^2-b^2+6b=(3-b)^2-b^2+6b=9+b^2-6b-b^2+6b=9