a(2a-3),a²(1-3a),3x(x²-2x-1),-2x²y(3x²-2x-3)
题目
a(2a-3),a²(1-3a),3x(x²-2x-1),-2x²y(3x²-2x-3)
(2x²-3xy+4y²)(-2xy),(-x)³·(-2xy²)³-4xy²(7x的5次方y的4次方-0.5xy³),
花间求值:(1)-3a²(a²-2a-3)+3a(a³-2a²-3a)+2012,其中a=2012
(2)x的n次方(x的n次方+9x-12)-3(3x的n+1次方-4x的n次方),其中x=-2,n=3
答案
a(2a-3)=2a^2-3a
a²(1-3a)=a^2-3a^3
3x(x²-2x-1)=3x^3-6x^2-3x
-2x²y(3x²-2x-3)=-6x^4y+4x^3y+6x^2y
(2x²-3xy+4y²)(-2xy)=-4x^3y+6x^2y^2-8xy^3
(-x)³·(-2xy²)³-4xy²(7x的5次方y的4次方-0.5xy³)
=-8x^6y^6-4xy^2(7x^5y^4-0.5xy^3)
=-8x^6y^6-28x^6y^6+2x^2y^5
=2x^2y^5-36x^6y^6
(1)-3a²(a²-2a-3)+3a(a³-2a²-3a)+2012,其中a=2012
=-3a²(a²-2a-3)+3a^2(a^2-2a-3)+2012
=2012
(2)x的n次方(x的n次方+9x-12)-3(3x的n+1次方-4x的n次方),其中x=-2,n=3
=x^n(x^n+9x-12)-3[3x^(n+1)-4x^n)
=x^2n+9x^(n+1)-12x^n-9x^(n+1)+12x^n
=x^2n
x=-2,n=3
=(-2)^(2*3)
=2^6
=64
举一反三
我想写一篇关于奥巴马的演讲的文章,写哪一篇好呢?为什么好
最新试题
热门考点
- 直接引语变间接引语题目与答案,1.My math teacher said to me,"You can do it better."
- 在交流电路中,当频率一定时,电容容量越大,容抗越大.是否正确?
- can you find the ( ) between the twins 填difference 还是 differences 为什么,谢谢
- 一桶油,连桶重12千克.用去一半后,连桶重7千克.油重多少千克?
- 菱形,矩形,正方形的判定方法.
- 小明家六月水费27元,九月85元.预测10月多少元
- there are lots of ___ in the fridge.A,foods B,apples C,egg
- unlcok everything是什么意思
- 电扇耗电功率等于额定功率吗?
- 方程ax^2+bx+c=0(a>0)有两实根,分别为3,-4,则不等式ax^2+bx+c>0的解集为