3x+120+380=5（x-40)

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!)+. 证明(x+1)(X+3)(x+5)(x+7)+15=(X+8x)+22(x+8x)+120 3x+120+380=5（x-40) 60％x+25=40 x+30％x=52 19-120％x=7 4分之3x-5％x=17.5 x-10％x=18 （1-25％）x=36 2x+30％x=9.2 x+2x+3x+4x+5x+6x+7x+8x+9x=9x-8x-7x-6x-5x-4x-3x-2x-x.x等于多少? (16x-13)/(4x-3)-(20x-24)/(4x-5)=(32x-30)/(8x-7)-(40x-43)/(8x-9)求x (32-2x)x=120 (x+3)^2=-x(x+5) 两个方程 (x-3/x-2)-(x-2/x-1)=(x-5/x4) -(x-4/x-3) 解方程x/(x-2)=2x/(x-3)+(1-x)/(x-5x+6) x-2x+3x-4x+5x.+99x-100x=25求解 2x+3x+4x+5x+x+6x+7x=100 x(x-2)-2x(x+1)-3x(x-5) 其中x=负½ x(x+1)+(x+2)+(x+3)+(x+4)+(x+5) = 27求x 2X+X+2x+5/3=120 计算x-2/5x+120=3/4x x-40-3/5x=100（求x, x+2/3x=60 x-3/5x=120 4x+18x=1x+2/3x=60 x-3/5x=120 4x+18x=132! x+3分之2 x=60 x-5分之3x=120 4x+18x=132x+3分之2 x=60 x-5分之3x=120 4x+18x=132