Đáp án:
M=12-/x-15/
do -/x-15/ lớn hơn hoặc bằng 0 với mọi x
nên 12-/x-15/ nhỏ hơn hoặc bằng 12
nên M nhỏ hơn hoặc bằng 12
dấu = xảy ra khi
-/x-5/=0
=>x=5
vậy GTLN của M là 12 khi x=5
Giải thích các bước giải :
`↓↓↓`
Ta tìm giá trị lớn nhất của M
`⇒ |x-15| ≥ 0 ⇔ -|x-15| ≤ 0`
`→ Max_M = 12`
Dấu "`=`" xảy ra khi : `|x-15| = 0`
`⇔ x-15=0`
`⇔ x=0+15 = 15`
Vậy `Max_M = 12` khi `x = 15`
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Giúp em với!!!!! Cần gấp lắm ạ!!!!!
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