解方程90/h=y+2要步驟

90/h = y+2

90 = h(y+2)

h = 90/(y+2)
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90/h = y+2

90 = h(y+2)

90 = hy+2h

90 - 2h = hy

(90 - 2h)h = y

y = (90 - 2h)h




2007-12-19 20:47:45 補充：
y = (90 - 2h)/h

............90/h=y+2
........90/hxh=(y+2)1/90
..............90=(y+2)h
(y+2)h/(y+2)=90/(y+2)
................h=90/(y+2)

........90/h=y+2
.........y+2=90/h
......y+2-2=90/h-2
.............y=90/h-2

h=90/(y+2)
y=90/h-2

假設h是7代入h=90/(y+2)
90/(7+2)=90/9=10

如果h是10
那麼y=90/h-2便成立
90/10-2=9-2=7

所以h=90/(y+2)和y=90/h-2是對的

假如只有以上一項資料，這數式有無限個解。
如h=1, y=88
h=2, y=43
h=3, y=28
...

因此，唯一可說的是對於y是任何一個有理數, h=90/(y+2)