x \(\varepsilon N\)
5x+3-5x=175
1. Cho hàm số y = f(x) có đạo hàm f '(x) = x2 -4x +3 ∀x \(\varepsilon\) R. Xác định m \(\varepsilon\) Z \(\varepsilon\) [-10,10] để hàm số g(x) = f ( x2 -5x + m) nghịch biến trên (-1,5)
2. Cho hàm số y = f(x) có đạo hàm f '(x) = x2 + 5x + 6 ∀ \(\varepsilon\) R. Xác định m \(\varepsilon\) Z \(\varepsilon\) [-20,20] để hàm số g(x) = f (x2 -10x - m) đồng biến trên (0,5)
5x(x-7)(x+7)-x(2x-1)^2-(x^3+4x^2-246x)-175
a) 5x - 7x - 16 = 224
b) 2x + 2y = 24 (x,y \(\varepsilon\)N / x < y)
a) 5x - 7x - 16 = 224
5x - 7x = 224 + 16
5x - 7x = 240
x( 5 - 7) = 240
x . (-2) = 240
Suy ra x = -120
b) 2x + 2y = 24
2x + 2y = 8 + 16
Suy ra x = 3 ; y = 4
a) 5x - 7x - 16 = 224
( 5 - 7 ) x -16 = 224
- 2 x - 16 = 224
- 2x = 224 + 16
- 2x = 240
x = 240 : ( - 2)
x = 240 x 2
x = 480
b -.- I don't know
Tìm \(x,y\varepsilon Z\)Sao cho: \(x^3+5x-12y=4\) .
P=(\(\frac{2x}{2x^2-5x+3}\)-\(\frac{5}{2x-3}\)) : (3+ \(\frac{2}{1-x}\))
a, Rút gọn P
b, P=? khi | 2x- 1|=3
c, x=? để P \(\varepsilon\)Z
d, Tìm x\(\varepsilon\)Z để P\(\varepsilon\)Z
\(P=\left(\frac{2x}{2x^2-5x+2}-\frac{5}{2x-3}\right):\left(3+\frac{2}{1-x}\right) \)(dk x khac 3/2 ; x khac 1)
\(P=\left(\frac{2x}{\left(2x-3\right)\left(x-1\right)}-\frac{5\left(x-1\right)}{\left(2x+3\right)\left(x-1\right)}\right):\left(\frac{3\left(x-1\right)}{x-1}-\frac{2}{x-1}\right)\)
\(P=\frac{2x-5x+5}{\left(2x-3\right)\left(x-1\right)}:\frac{3x-3-2}{x-1}\)
\(P=\frac{-\left(3x-5\right)}{\left(2x-3\right)\left(x-1\right)}\cdot\frac{x-1}{3x-5}\)
\(P=\frac{-1}{2x-3}\)
b) TC: \(|2x-1|=3\)
TH1) \(|2x-1|=2x-1\)khi \(x\ge\frac{1}{2}\)
2x-1=3 suy ra x=2 ( thoa dk)
TH2) \(|2x-1|=-2x+1\)khi \(x< \frac{1}{2}\)
-2x+1=3 suy ra x=-1 ( thoa dk)
khi x= 2 thi P=-1
khi x= -1 thi P=1/5
c) de P thuoc Z thi \(-\frac{1}{2x-3}\)thuoc Z
suy ra \(\frac{1}{3-2x}\)thuoc Z
suy ra 3-2x thuoc \(Ư\left(1\right)\in\left\{\pm1\right\}\)
khi 3-2x=1 thi x= 1 (ko thoa dk x khac 1)
khi 3-2x=-1 thi x=2(thoa dk)
vay x=2 thi P thuoc Z
d) giai tg tu cau c
175-5x(x-10)=25
\(175-5\times\left(x-10\right)=25\)
\(\Rightarrow5\times\left(x-10\right)=175-25\)
\(\Rightarrow5\times\left(x-10\right)=150\)
\(\Rightarrow x-10=150:5\)
\(\Rightarrow x-10=30\)
\(\Rightarrow x=30+10\)
\(\Rightarrow x=40\)
Học tốt #
\(175-5\left(x-10\right)=25\)
\(\Leftrightarrow5\left(x-10\right)=150\)
\(\Leftrightarrow x-10=30\)
\(\Leftrightarrow x=40\)
hok tốt nhé!
5 * (x- 10 ) = 25+ 175
5* (x- 10 ) = 200
x- 10 = 200/ 5
x- 10 = 40
x = 40 + 10
x =50
Tìm \(x,y\varepsilon Z\) Sao cho: \(x^3+5x-12y=4\)
tìm x\(\varepsilon\) z để A=\(\dfrac{10x+15}{5x+1}\)
10x+15\(⋮\)5x+1
\(\Rightarrow\)10x+2+13\(⋮\)5x+1
\(\Rightarrow\)(10x+2)+13\(⋮\)5x+1
\(\Rightarrow\)13\(⋮\)5x+1
\(\Rightarrow\)5x+1\(\in\)Ư(13)
Ư(13)\(\in\)
10x+15⋮5x+1
⇒10x+2+13⋮5x+1
⇒(10x+2)+13⋮5x+1
⇒13⋮5x+1
⇒5x+1∈Ư(13)
Ư(13)∈\(\left\{{}-13;-1;1;13}\)
⇒5x+1∈\(\left\{{}-13;-1;1;13}\)
⇒5x∈(-14;-2;0;12)
⇒x∈(-14/5;-2/5;0;12/5)
P= (\(\frac{2x}{2x^2-5x+3}\)_ \(\frac{5}{2x-3}\)) :(3+ \(\frac{2}{1-x}\))
a, Rút gọn P
b, P=? để P>1
d, Tìm x\(\varepsilon\)Z để P\(\varepsilon\)Z