函數既問題

0 ⤊

已知ｙ＝2x-5
當函數的值是15時,求x的值

2006-10-26 16:42:42 · 2 個解答 · 發問者 Jeff 6 in 科學 ➔ 數學

要式

2006-10-26 16:44:32 · update #1

唔明

2006-10-26 16:53:59 · update #2

ｙ＝2x-5

sub. y = 15
2x - 5 = 15
2x = 20
x = 10

Therefore , x = 10 when y = 15

2006-10-26 16:45:11 · answer #1 · answered by J 7 · 0⤊ 0⤋

﹛y=2x-5　　－－－－－１
﹛y=15　　－－－－－２

代１入２

2x - 5 = 15

2x = 20

x = 10

2006-10-26 17:10:25 · answer #2 · answered by ? 3 · 0⤊ 0⤋