Question

1.先化简,后求值.其中x=-3,y=3分之1

Answer 1

9.先化简,后求值.其中x=-3,y=3分之1
3xy^2(-3分之1x^2y+4x^3y^2)-4x^2y(-4分之xy^2)*(-4xy)
=-x^3y^3+12x^4y^4-12x^4y^4=-x^3y^3=1
10.解方程：6x(1-x)-4x(1-x)=16-2(x^2-2)
6X-6X^2-4X+4X^2=16-2X^2+4 2X-2X^2=16-2X^2+4 X=10
11.(y+3)(y-6)=Y^2-3Y-18
12.(2x+1)(x-1)=2X^2-X-1
13.(ab-2分之1)(ab-3分之1)= A^2B^2 -5/6AB+ 1/6
14.(x-1)(x-2)(x+3)=(X-3X+2)*(X+3) =X^3-7X+6
15.-(a+3b)(a-5b)=-(a^2-5ab+3ab-15b^2)