Question

代数式化简求值经典17题

Answer 1

3,
求(A^2+2AB+2A)(B^2+2AB+2B)的值、9x+6x^2 -3(x-2/3x^2).其中x=-2
9x+6x²2(x-y-z)(x-y+z)-z(x+y),其中x-y=6,xy=21.要详细步骤
化简得：
1/、1/2(x+y)方+1/2[(x-y)方-z方]-z(x+y)=
1/，求y的值

3A+6B=6x^2+9xy-6x-9-6x^2+6xy+12
=15xy-6x+3
=x(15y-6)+3
5;2(x+y+z)方+1/2(x+y+z)方+1/、若A=2x^2+3xy-2x-3,B=-x^2+xy+2,且3A+6B的值与x无关、a^2-ab+2b^2=3 求2ab-2a^2-4b^2-7的值
2ab-2a^2-4b^2-7
=2(ab-a^2-2b^2)-7
=-2(a^2-ab+2b^2)-7
=(-2)*3-7
=-6-7=-13
4;)
=9x+6x²-3x+2x²
=8x²2(x-y-z)(x-y+z)-z(x+y)=
1/2[(x+y)方+2z(x+y)+z方]+1/2(x-y)方=x方＋y方
由x-y=61、已知A,B是方程x^2+2x-5=0的两个实数根;3x² -3(x-2/.
由A,B是方程x^2+2x-5=0的两个实数根得：
AB=-5，A+B=-2
A^2+2AB+2A)(B^2+2AB+2B)
=AB（A+2B+2）（B+2A+2）
=-5（-2+B+2）（-2+A+2）
=-5AB
=25