4(X+1)^2-(2X+5)(2x-5)
=4(X^2+2X+1)-4X^2+25
=8X+26
3(Y-Z)^2-(2Y+Z)(-Z+2Y)
=3(Y^2-2YZ+Z^2)-(4Y^2-Z^2)
=4Z^2-6ZY-Y^2
=
[X(X^2Y^2-XY)-Y(X^2-x^3Y)]÷3X^2Y
=(X^2Y(XY-1)-YX^2(1-XY)}/3X^2Y
=(XY-1)(X^2Y+X^2Y)/3X^2Y
=2/3*(XY-1)
解方程;(X+7)(X+5)-(X+1)(X+5)=42
(X+5)(X+7-X-1)=42
(X+5)*6=42
X+5=7
X=2
解不等式; X(2X-5)2X^2-3X-4
2X^2-5X2X^2-3X-4
-2X4
X2
(X+1)(X+3)+8X(X+5)(X-5)-2
X^2+4X+3+8XX^2-25-2
12X-30
X-5/2
X-2.5