已知多项式x²+2x+5的值是7,求多项式3x²+6x+3的值.(提示:x²+2x=2)
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/04 14:05:34
![已知多项式x²+2x+5的值是7,求多项式3x²+6x+3的值.(提示:x²+2x=2)](/uploads/image/z/1963458-18-8.jpg?t=%E5%B7%B2%E7%9F%A5%E5%A4%9A%E9%A1%B9%E5%BC%8Fx%26%23178%3B%2B2x%2B5%E7%9A%84%E5%80%BC%E6%98%AF7%2C%E6%B1%82%E5%A4%9A%E9%A1%B9%E5%BC%8F3x%26%23178%3B%2B6x%2B3%E7%9A%84%E5%80%BC.%EF%BC%88%E6%8F%90%E7%A4%BA%EF%BC%9Ax%26%23178%3B%2B2x%3D2%EF%BC%89)
已知多项式x²+2x+5的值是7,求多项式3x²+6x+3的值.(提示:x²+2x=2)
已知多项式x²+2x+5的值是7,求多项式3x²+6x+3的值.
(提示:x²+2x=2)
已知多项式x²+2x+5的值是7,求多项式3x²+6x+3的值.(提示:x²+2x=2)
解
x²+2x+5=7
∴x²+2x=2
∴3x²+6x+3
=3(x²+2x)+3
=3×2+3
=6+3
=9
9,分析请追问。