作业帮(x^2-7x)^2+6x-42x 25x^2-16y^2-4z+16yz
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(x^2-7x)^2+6x-42x 25x^2-16y^2-4z+16yz
(x^2-7x)^2+6x-42x
25x^2-16y^2-4z+16yz
(x^2-7x)^2+6x-42x 25x^2-16y^2-4z+16yz
(x^2-7x)^2+6x-42
=[x(x-7)]^2+6[x-7]
=[x-7][x^2(x-7)+6 ]
=[x-7][x^3-7x^2+6]
=[x-7][x^2(x-1)-6(x^2-1)]
=[x-7][x^2(x-1)-6(x+1)(x-1)]
=[x-7][(x-1)(x^2-6x-6)]
25x^2-16y^2-4z^2+16yz
=25x^2-4[4y^2-4yz+z^2]
=25x^2-4[2y-z]^2
=[5x+2(2y-z)][5x-2(2y-z)]
=[5x+4y-2z][5x-4y+2z]
用完全平方公式
*-----------------------------------------------*| 6 4 X | 8 X X | X X 5 || X X X | X X X | X 7 8 || X X X | X X X | X X X ||---------------+---------------+--------------- || X X X | X X X | 5 1 X || X X X | X 6 X | X X X || 8 X X | 3 5 X | 2 X X ||
填九宫格帮帮忙.x x 6 x x 7 x x 98 x x x 3 x 1 x x 9 x x 6 x 5 x 3 x x x 3 x x x x 1 8x x x 9 x 1 x x x2 1 x x x x 6 x x x 6 x 7 x 3 x x 1 x x 9 x 2 x x x 47 x x 8 x x 5 x x
x/x-2+x-9/x-7=x+1/x-1+x-8/x-6,
x/x-2+x-9/x-7=x+1/x-1+x-8/x-6,
求一个数独答案X X X 9 X X X 8 2 X 6 3 X X 1 4 X 99 X 8 X X X X X XX X X 6 7 X 3 X XX 4 6 X 5 X 2 9 XX X 7 X 2 3 X X XX X X X X X 7 X 17 X 4 3 X X 6 2 X6 3 X X X 7 X X X
x(x*x-6x-9)-x(x*x-8x-15)+2x(3-x)
难倒爱因斯坦的九宫格X 7 X | X 8 1 | X X X |X X X | X 4 X | 7 5 9 |X X 5 | 7 X 9 | X 1 4 |5 X X | X X 8 | 3 9 X |3 9 6 | 4 X 7 | X X 2 |X 8 7 | 9 X X | X X X |4 X X | 6 X 5 | X X X | X X 4 | X X 1 |2 X X | X X X | X X X | X 3 X | X X X |X 6
x+2x+3x+4x+5x+6x+7x+8x+9x=9x-8x-7x-6x-5x-4x-3x-2x-x.x等于多少?
如下9*9宫图如何填x x x 1 x x x 2 9x x 5 x x x x x 4x 6 8 x x x x x xx x x 7 x x 5 x xx 2 x x 6 x x 8 xx x 3 x x 9 x x xx x x x 5 x 1 6 x 4 x x x 3 x x x x 7 x x x x 2 x x x
解九宫格题目（X为未知数）9 X 2 X 7 X 8 X XX X 4 X X 9 X 6 X1 3 X 5 X X X X 24 X X 8 5 X X 1 XX 8 9 4 X 1 6 7 XX 1 X X 3 6 X X 88 X X X X 2 X 3 6X 5 X 6 X X 9 X XX X 7 X 4 X 2 X 1
2x+3x+4x+5x+x+6x+7x=100
x+2/x+1-x+4/x+3=x+6/x+5-x+8/x+7 x=?
matlab解决约束非线性规划问题myfun.mfunction f=myfun(x)f=x(1)*x(13)+x(2)*x(14)+x(3)*x(15)+x(25)+1.697*(x(4)*x(16)+...x(5)*x(17)+x(6)*x(18)+x(26))+0.575*(x(7)*x(19)+x(8)*x(20)...+x(9)*x(21)+x(27))+0.723*(x(10)*x(22)+x(11)*x(23)+x(12)*x(24));
matlab解决约束非线性规划问题myfun.mfunction f=myfun(x)f=x(1)*x(13)+x(2)*x(14)+x(3)*x(15)+x(25)+1.697*(x(4)*x(16)+...x(5)*x(17)+x(6)*x(18)+x(26))+0.575*(x(7)*x(19)+x(8)*x(20)...+x(9)*x(21)+x(27))+0.723*(x(10)*x(22)+x(11)*x(23)+x(12)*x(24));
x+2x-3x-4x+5x+6x-7x.-196x+197x+198x-199x-200x 等于多少
解决数独问题x 1 x 7 x x x 3 xx x x x 4 x 2 x x9 x 3 6 x 8 7 x 58 x x x x 9 x x xx x 2 x 5 x x x 4x 3 x x x x 6 x xx x x x x x x x 26 x x x x x x x 7x 5 4 1 7 x 9 8 x这道题我用了很多办法都没有头绪,请帮忙的朋友把解题的思
x/2+x/6+x/12+x/20+x/30+x/42+x/56=7/8 其中x未知数,求x,要求简便.
解分式方程：1/X-2+1/X-6=1/X-7+1/X-11/X-2+1/X-6=1/X-7+1/X-11/(x-2)-1/(x-1)=1/(x-7)-1/(x-6)(x-1-x+2)/(x-2)(x-1)=(x-6-x+7)/(x-7)(x-6)1/(x-2)(x-1)=1/(x-7)(x-6)(x-2)(x-1)=(x-7)(x-6)x^2-3x+2=x^2-13x+4213x-3x=42-210x=40x=4 为什么要移向才能解