初1的数学题有人会么,商分50
1.x⒉+________-8x⒉-1=2x⒊+7x-3
2.若(x+1)⒉+4｜y-6｜=0,则7x+8y+4x-6y的值为
3.[x(x⒊y⒉)⒉-2(x⒉y)⒊·(-xy⒉)⒊=____
4.6a⒋b⒊+12a⒊b⒋-8a⒊b⒉=2a⒊b⒉(___________________)
5.若3х+⒈·2χ+⒈=6⒉х-⒊,则x=_____________
6.当3m+2n-3=0时,则8м·4и=___________
7.已知代数式14x+5-21x⒉=-2,求6x⒉-4x+5的值
参考答案:1.x⒉+(2x^3+7x^2+7x-2)-8x⒉-1=2x⒊+7x-3
2.若(x+1)⒉+4｜y-6｜=0,则7x+8y+4x-6y的值为
(x+1)=0
y-6=0
x=-1
y=6
7x+8y+4x-6y=11x+2y=-11+12=1
3.[x(x⒊y⒉)⒉-2(x⒉y)⒊]·(-xy⒉)⒊=____
=x*x^6y^4-2x^6y^3*(-x^3y^6)
=x^7y^4+2x^9y^9
4.6a⒋b⒊+12a⒊b⒋-8a⒊b⒉=2a⒊b⒉(3ab+6b^2-4)
5.若3х+⒈·2χ+⒈=6⒉х-⒊,则x=_____4________
3^(x+1)*2^(x+1)=6^(2x-3)
(3*2)^(x+1)=6^(2x-3)
x+1=2x-3
x=4
6.当3m+2n-3=0时,则8м·4и=_______8____
8^m*4^n=(2^3)^m*(2^2)^n=2^3m*2^2n=2^(3m+2n)=2^3=8
7.已知代数式14x+5-21x⒉=-2,求6x⒉-4x+5的值
21x^2-14x-7=0
3x^2-2x-1=0
3x^2-2x=1
6x^2-4x+5=2(3x^2-2x)+5=2*1+5=7