1.（3X+2Y)+(4X+3Y)其中X=5,Y+3
解：原式=3X+2Y+4X+3Y=7X+5Y
當X=5,Y=3時
原式=5*7+（-3）*5+20?
2.(5a^2-3b^2)+(a^2+b^2)-(5a^2+3b^2),其中a=-1,b=1?
=5a^2-3b^2+a^2+b^2-5a^2-3b^2?
=a^2-5b^2?
=(-1)^2-5*1^2?
=1-5?
=-4
1.若A=2x^2+3xy-2x-3,B=-x^2+xy+2,且3A+6B的值與x無關，求y的值?
解：?
3A+6B=6x^2+9xy-6x-9-6x^2+6xy+12?
=15xy-6x+3?
=x(15y-6)+3?
5、9x+6x^2 -3(x-2/3x^2).其中x=-2?
9x+6x? -3(x-2/3x?)?
=9x+6x?-3x+2x
=8x?+6x?
=8×(-2)?+6×(-2)?
=32-12?
=20?
整式化簡求值題及答案
簡單壹點，去分母的方程也行，要有答案。
越多越好，我有追加 ,最好是原創的，分母的方程也來點。
來自匿名用戶的提問
最佳答案由提問者推薦
1.（3X+2Y)+(4X+3Y)其中X=5,Y+3
解：原式=3X+2Y+4X+3Y=7X+5Y
當X=5,Y=3時
原式=5*7+（-3）*5+20?
2.(5a^2-3b^2)+(a^2+b^2)-(5a^2+3b^2),其中a=-1,b=1?
=5a^2-3b^2+a^2+b^2-5a^2-3b^2?
=a^2-5b^2?
=(-1)^2-5*1^2?
=1-5?
=-4?
3.2(a^2b+ab^2)-2(a^2 b-1)-2ab^2 -2其中a=-2,b=2?
=2a^2b+2ab^2-2a^2b+2-2ab^2-2?
=0?
1、已知A,B是方程x^2+2x-5=0的兩個實數根,?
求(A^2+2AB+2A)(B^2+2AB+2B)的值.?
由A,B是方程x^2+2x-5=0的兩個實數根得：?
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?
2、1/2(x+y+z)方+1/2(x-y-z)(x-y+z)-z(x+y),其中x-y=6,xy=21.要詳細步驟?
化簡得：?
1/2(x+y+z)方+1/2(x-y-z)(x-y+z)-z(x+y)=?
1/2[(x+y)方+2z(x+y)+z方]+1/2[(x-y)方-z方]-z(x+y)=?
1/2(x+y)方+1/2(x-y)方=x方＋y方?
由x-y=6,xy=21得，x方＋y方＝（x-y）方＋2xy＝78?
3、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、若A=2x^2+3xy-2x-3,B=-x^2+xy+2,且3A+6B的值與x無關，求y的值?
解：?
3A+6B=6x^2+9xy-6x-9-6x^2+6xy+12?
=15xy-6x+3?
=x(15y-6)+3?
5、9x+6x^2 -3(x-2/3x^2).其中x=-2?
9x+6x? -3(x-2/3x?)?
=9x+6x?-3x+2x
=8x?+6x?
=8×(-2)?+6×(-2)?
=32-12?
=20?
6、1/4(-4x^2+2x-8)-(1/2x-1),其中x=1/2?
1/4(-4x?+2x-8)-(1/2x-1)?
=-x?+1/2x-2-1/2x+1?
=-x?-1?
=-(1/2)?-1?
=-1/4-1?
=-5/4?
7、3x'y-[2x'y-(2xyz-x'z)-4x'z]-xyz,其中x=-2,y=-3,z=1,?
:3x'y-[2x'y-(2xyz-x'z)-4x'z]-xyz?
=3x'y-2x'y+2xyz-x'z+4x'z-xyz?
=x'y-xyz+3x'z?
=4*(-3)-2*3*1+3*4*1?
=-12-6+12?
=-6?
8、(5a^2-3b^2)+(a^2+b^2)-(5a^2+3b^2),其中a=-1,b=1?
=5a^2-3b^2+a^2+b^2-5a^2-3b^2?
=a^2-5b^2?
=(-1)^2-5*1^2?
=1-5?
=-4?
9、2(a^2b+ab^2)-2(a^2 b-1)-2ab^2 -2其中a=-2,b=2?
=2a^2b+2ab^2-2a^2b+2-2ab^2-2?
=0?
10、(X-2分之1Y-1)(X-2分之1Y+1)-(X-2分之1Y-1)的平方?
其中X=1.7,Y=3.9(先化簡再求值)?
[(X-2分之1Y)-1][(X+2分之1Y)+1]-(X-2分之1Y-1)平方?
=(X+2分之1Y)平方-1-(X-2分之1Y)平方+2(X-2分之1Y)-1?
=(X+2分之1Y)平方-(X-2分之1Y)平方+2(X-2分之1Y)-2?
=2XY+2X-Y-2?
=3.9*2.4+1.4?
=10.76
2.