中二數學 公式

1. (6xy+18xz)/(8yz+24zz)
..=6x(y+3z)/8z(y+3z)
..=6x/8z
............//

2. (xx+2xy)/(xx) ÷ (10y+5x)/(10xyy)
..=(xx+2xy)/(xx) * (10xyy)/(10y+5x)
..=x(x+2y)/x(x) * 5(2xyy)/5(2y+x)
..=(x+2y)/(x) * (2xyy)/(2y+x)
..=2yy
.........//

3. (-3ab^2)3 / a^3b+ab^3 × -a^2－b^2 / (-9a)^2
..=-9abb/ab(aa+bb) * -(aa+bb)/(81aa)
..=9b/(aa+bb) * (aa+bb)/-81aa
..=9b/-81aa
..= -(b/9aa)
................//

4. x/x^2+2x － 1/x－2
..=x/(xx+2x) - 1/(x-2)
..=x/x(x+2) - 1/(x-2)
..=1/(x+2) - 1/(x-2) ?????????題目不清楚..錯的話請見諒...我會補充的

5. 6x-15 / 3x－3 + 4x+2 / 2－2x <-------會不會打錯題目...我試着改4x+1=>4x+2
..=3(2x-5)/3(x-1) + 2(2x+1)/2(1-x)
..=(2x-5)/(x-1) + (2x+1)/(1-x)
..=(2x-5/(x-1) - (2x+1)/(x-1)
..=[(2x-5)-(2x+1)]/(x-1)
..=(-6)/(x-1)
..=6/(1-x)
.............//

6. 6x/3x^2+3x ＋ x－1/2(x+1)^2 － x/6x^2－6
..=3x(2)/3x(x+1) + x-1/2(x+1)(x+1) - x/6(xx-1)
..=2/(x+1) + ..................(好像沒得做了....會不會是打錯題?不是的話我就不懂了)

7. x/a+y/b=1 [y]
..........y/b=1-x/a
.............y=b(1-x/a)
............................//

8. y=3nx/4+(2n-1)x [n]
.......y=3nx/4 + (2n-1)x <----------是不是這樣...
.....4y=3nx + 8nx - 8x
.....4y=11nx - 8x
..11nx=4y+8x
.......n=(4y+8x)/11x
............................//