3x+5x+7y=10000
用递归法求y=x-(x*x*x/3!)+(x*x*x*x*x/5!)-(x*x*x*x*x*x*x/7!)+.
若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
y=(x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9)(x-10)的导数在x=1
y-x=3 7x+5y=-9
{x+y=5{3x-7y=11
(7y-3x)-(8y-5x)=
{y=x+3,7x+5y+9;
x+y=3 x+2y=9 3/x+1=y y-x=3 y=2x-3 y-3x=1 2(x+1)-y=6 7x-5y=-9
5x^3y-6x-7x^3y-8x=
先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y
7x-3y/5=5x-y/3-x+y/2 x-1/5=y+1/3