1. Tìm x, biết :
a) 9 + x/ 15 - x = 5/7
b) x +x :5 * 9,5 + x : 4 * 10 = 315
2. Tính nhanh:
2018 *2017-1/2016*2018+201
a)\(\frac{x+1}{5}+\frac{x+1}{6}+\frac{x+1}{7}=\frac{x+1}{8}+\frac{x+1}{9}\)
b)\(\frac{x+6}{2015}+\frac{x+5}{2016}+\frac{x+4}{2017}=\frac{x+3}{2018}+\frac{x+2}{2019}+\frac{x+1}{2010}\)
c)\(\frac{x+6}{2016}+\frac{x+7}{2017}+\frac{x+8}{2018}=\frac{x+9}{2019}+\frac{x+10}{2020}+1\)
d)\(\frac{x-90}{10}+\frac{x-76}{12}+\frac{x-58}{14}+\frac{x-36}{16}+\frac{x-15}{17}=15\)
ai xong nhanh nhất và đúng em xin gửi 2 SP ạ
a) \(\frac{x+1}{5}+\frac{x+1}{6}+\frac{x+1}{7}=\frac{x+1}{8}+\frac{x+1}{9}\)
\(\Leftrightarrow\frac{x+1}{5}+\frac{x+1}{6}+\frac{x+1}{7}-\frac{x+1}{8}-\frac{x+1}{9}=0\)
\(\Leftrightarrow\left(x+1\right).\left(\frac{1}{5}+\frac{1}{6}+\frac{1}{7}-\frac{1}{8}-\frac{1}{9}\right)=0\)
\(\Leftrightarrow x+1=0\)
\(\Leftrightarrow x=0-1\)
\(\Rightarrow x=-1\)
Vậy \(x=-1.\)
Mình chỉ làm câu a) thôi nhé.
Chúc bạn học tốt!
Tìm x biết
a)x/2+x/3+x/4+x/5=0
b)x+1/2019 + x+2/2018 = x+3/2017 + x+4/2016
a) \(\frac{x}{2}+\frac{x}{3}+\frac{x}{4}+\frac{x}{5}=0\)
\(\frac{77x}{60}=0\)
\(77x=0.60\)
\(77x=0\)
\(x=0\)
\(\frac{a+1}{2019}+\frac{a+2}{2018}=\frac{a+3}{2017}+\frac{a+4}{2016}\Leftrightarrow\frac{a+2020}{2019}+\frac{a+2020}{2018}=\frac{a+2020}{2017}+\frac{a+2020}{2016}\)
\(\left(a+2020\right)\left(\frac{1}{2019}+\frac{1}{2018}-\frac{1}{2017}-\frac{1}{2016}\right)=0\Rightarrow a+2020=0\Leftrightarrow a=-2020\)
1. Cho biểu thức B :
\(B=x^{2017}-2018.x^{2016}+2018.x^{2015}-2018.x^{2014}+...-2018.x^2+2018.x-1\)
TÍNH GIÁ TRỊ BIỂU THỨC VỚI x=2017
3. Cho : \(\frac{xy+1}{9}=\frac{yz+2}{15}=\frac{xz+3}{27}\)và xy +yz + zx=11 . TÌM x,y,z
Tim x
\(\frac{x+2015}{5}+\frac{x+2016}{4}=\frac{x+2017}{3}+\frac{x+2018}{2}\)
2/ tim x
\(\frac{x+2015}{5}+\frac{x+2016}{6}=\frac{x+2017}{7} +\frac{x+2018}{8}\)
3/ tim x
\(\frac{1}{3}+\frac{1}{6}+\frac{99}{101}+\frac{1}{15}+... +\frac{1}{x\left(2x+1\right)}=\frac{1}{10}\)
\(\frac{x+2015}{5}+\frac{x+2016}{4}=\frac{x+2017}{3}+\frac{x+2018}{2}\)
\(\Leftrightarrow\left(\frac{x+2015}{5}+1\right)+\left(\frac{x+2016}{4}+1\right)=\left(\frac{x+2017}{3}+1\right)+\left(\frac{x+2018}{2}+1\right)\)
\(\Leftrightarrow\frac{x+2020}{5}+\frac{x+2020}{4}-\frac{x+2020}{3}-\frac{x+2020}{2}=0\)
\(\Leftrightarrow\left(x+2020\right)\left(\frac{1}{5}+\frac{1}{4}-\frac{1}{3}-\frac{1}{2}\right)=0\)
\(\Leftrightarrow x+2020=0\)vì \(\frac{1}{5}+\frac{1}{4}+\frac{1}{3}+\frac{1}{2}\ne0\)
\(\Leftrightarrow x=-2020\)
Cảm ơn bạn rất nhiều mình đã hiểu rồi
Chúc bạn học tốt nhé
Tìm giá trị nhỏ nhất
P = 2018/x^2+2x+2017
Q = a^2018+2017/a^2018+2015
A = (x-3y)^2020+(y-2018)^2018
B = (x+y-5)^8+(x-2y)^4+2016
C = \x-2017\+\x-2018\
D = \x-2010\+\x-2011\+\x+2012\
Tìm x, biết:
a) | x - 2017 | = 2017 - x
b) | x - 2016 | + | x - 2017 | = 2018
c) | x - 1 | + | x + 3 | = 4
Lâp bảng xét dấu
2016 2017
x-2016 _ 0 + +
x-2017 _ _ 0 +
Nếu x<2016 thì |x-2016|=2016-x,|x-2017|=2017-x
Ta có 2016-x+2017-x=2018
4033-2x=2018
2x=2015
x=1007,5
Nếu 2016<=x<=2017thif |x-2016|=x-2016;|x-2017|=2017-x
Ta có x-2016+2017-x=2018
ox+1=2018
0x=2017 (vô lí)
Nếu x>=2017 thi |x-2016|=x-2016;|x-2017|=x-2017
Ta có x-2016+x-2017=2018
2x-4033=2018
2x=6051
x=3025,5
Vậy x=1007,5 hoăc x=3025,5
TÌm x,y biết
a, x/2015+x-1/2016=x+1/1007
b, (x-1)^2018+|y+2017|=0
c,(x-9)^x+10=(x-9)^x+8
mọi người giúp mk với,mk đang cần gấp
2. Tính P=(1+x/y)*(1+z/x)*(1+z/y). Biết x+y+z=0 và x,y,z #0
3. Tính Q= 5.y^10-y^15+2016. Biết (x+1)^2016+(y-1)^2018=0
2. Tính P=(1+x/y)*(1+z/x)*(1+z/y). Biết x+y+z=0 và x,y,z #0
3. Tính Q= 5.y^10-y^15+2016. Biết (x+1)^2016+(y-1)^2018=0