Tim x , biet
(2x-1) ^2 + (x+3)^2 -5(x+7)(x-7) = 0
moi ng lam nhanh giup ! Thanks
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Tim x, biet:
1) -5.(2-x)+4.(x-3)=10.x-15
2) 2.(7x-14)-7.(3x-5)=28
3) 17+x=7+6.x
4) 4.!x-2!=8
5) 4.x-5.(-3+x)=7
mik dag gap lam tra loi nhanh va chi tiet giup mik
Tim x biet: (\(2x^2+7\))x(\(-3x-9\))<\(0\)
Giup mik voi ai nhanh mik tik cho^-^
Nho lam day du ho mik nhe,Thanks=))
ta thấy \(2x^2+7>0\)
\(=>-3x-9< 0\)
\(=>-3x< 9\)
\(=>x>-3\)
vậy...
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1 tim x , biet
a) x - 7va 5/8 = 1 va 1/4
b) x + 7 va 5/8 = 9 va 1/4
c) ( x - 7 va 5/8 ) : 1/2 = 3
d) x / 1x3 + x/3x5+.....+x/97x99=99
giup mik nhanh nha . mik can gap lam
\(a,x-7\frac{5}{8}=1\frac{1}{4}\)
=> \(x-\frac{61}{8}=\frac{5}{4}\)
=> \(x=\frac{5}{4}+\frac{61}{8}\)
=> \(x=\frac{10}{8}+\frac{61}{8}=\frac{71}{8}=8\frac{7}{8}\)
\(b,x+7\frac{5}{8}=9\frac{1}{4}\)
=> \(x+\frac{43}{5}=\frac{37}{4}\)
=> \(x=\frac{37}{4}-\frac{43}{5}=\frac{13}{20}\)
\(c,\left[x-7\frac{5}{8}\right]:\frac{1}{2}=3\)
=> \(\left[x-\frac{61}{8}\right]=3\cdot\frac{1}{2}\)
=> \(\left[x-\frac{61}{8}\right]=\frac{3}{2}\)
=> \(x-\frac{61}{8}=\frac{3}{2}\)
=> \(x=\frac{3}{2}+\frac{61}{8}=\frac{12}{8}+\frac{61}{8}=\frac{73}{8}=9\frac{1}{8}\)
d, \(\frac{x}{1\cdot3}+\frac{x}{3\cdot5}+\frac{x}{5\cdot7}+...+\frac{x}{97\cdot99}=99\)
=> \(\frac{x}{2}\left[\frac{2}{1\cdot3}+\frac{2}{3\cdot5}+\frac{2}{5\cdot7}+...+\frac{2}{97\cdot99}\right]=99\)
=> \(\frac{x}{2}\left[1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{97}-\frac{1}{99}\right]=99\)
=> \(\frac{x}{2}\left[1-\frac{1}{99}\right]=99\)
=> \(\frac{x}{2}\cdot\frac{98}{99}=99\)
=> \(\frac{98x}{198}=99\)
=> 98x = 99 . 198
=> 98x = 19602
=> x = 19602 : 98 = 9801/49
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a) \(x-7\frac{5}{8}=1\frac{1}{4}\)
=> \(x=\frac{5}{4}+\frac{61}{8}\)
=> \(x=\frac{71}{8}\)
b) \(x+7\frac{5}{8}=9\frac{1}{4}\)
=> \(x=\frac{37}{4}-\frac{61}{8}\)
=> \(x=\frac{13}{8}\)
c) \(\left(x-7\frac{5}{8}\right):\frac{1}{2}=3\)
=> \(x-\frac{61}{8}=3.\frac{1}{2}\)
=> \(x-\frac{61}{8}=\frac{3}{2}\)
=> \(x=\frac{3}{2}+\frac{61}{8}\)
=> \(x=\frac{73}{8}\)
d) \(\frac{x}{1.3}+\frac{x}{3.5}+...+\frac{x}{97.99}=99\)
=> \(x.\frac{1}{2}.\left(\frac{2}{1.3}+\frac{2}{3.5}+...+\frac{2}{97.99}\right)=99\)
=> \(\frac{1}{2}x\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+....+\frac{1}{97}-\frac{1}{99}\right)=99\)
=> \(x\left(1-\frac{1}{99}\right)=99:\frac{1}{2}\)
=> \(x.\frac{98}{99}=198\)
=> \(x=198:\frac{98}{99}=\frac{9801}{49}\)
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\(b,\text{ }x+7\frac{5}{8}=9\frac{1}{4}\)
\(x=9\frac{1}{4}-\left(7+\frac{5}{8}\right)\)
\(x=9+\frac{1}{4}-7-\frac{5}{8}\)
\(x=\left(9-7\right)+\left(\frac{1}{4}-\frac{5}{8}\right)\)
\(x=2+-\frac{3}{8}\)
\(x=2\frac{-3}{8}\)
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Xem thêm câu trả lời
Tim x biet :
7x+2 +7x+1+7 /57 = 52x +52x+1+52x+3 /131
Nhanh tay giai giup to di may than dong toan oi
giup mik voi tim x biet
1, 5-(3x+6)>-2x+1
2, -7.(x+2)-3x<6-11x
3, (x+1).(x+2)-x.(x+3)<4-x
4, 6-2x>17+(4-x)
TIM X
a) (7/2+2x)x8/3=16/3
b) [2x+3]=5
c) x-2/4=5+x/3
lam on giup toi nhe ban
Tim x biet:
(2x-1)5=(2x-1)7
Tim cac so nguyen to x , y thoa man:
(x-2)2.(y-3)2=4
trinh bay cach lam nhe
(2x-1)5=(2x-1)7
=>x=0;1;\(\frac{1}{2}\)
(x-2)2.(y-3)2=4
phân tích rồi kẻ bảng ra
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tim gia tri cua m,biet rang 1 trong 2 phuong trinh sau day nhan x=-1 lam nghiem,phuong trinh con lai nhan x=5 lam nghiem : (1-x)(x^2+1)=0 va (2x^2+7)(8-mx)=0
(1-x)(x^2+1)=0 chắc chắn sẽ không nhận x=-1 hoặc x=5 làm nghiệm rồi
(2x^2+7)(8-mx)=0
=>8-mx=0
Nếu 8-mx=0 nhận x=-1 làm nghiệm thì m+8=0
=>m=-8
Nếu 8-mx=0 nhận x=5 làm nghiệm thì 8-5m=0
=>m=8/5
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1. tinh :
a) 15/8 + 3/4 - 5/12
b) 11/24 x 12/33 + 5/6
c) 15/8 + 7/24 : 5/8
2 . tim x, biet :
a) x + 5/8 : 3/4 = 17/9
b) x - 5/9 x 18/15 = 1/3
c) x x7/8 - 5/8 = 13/24
d) X x1/7 + X x 1/4 + X x 1/4 =18
giup mik nhanh nha. mik can gap lam
a)15/8+3/4-5/12
=45+18-10/24
=53/24
b)11/24.12/33+5/6
=11.12/12.2.11.3+5/6
=1/6+5/6
=6/6=1
c)15/8+7/24:5/8
=15/8+7/24.8/5
=15/8+7.8/3.8.5
=15/8+7/15
=đề sai, nếu đúng thì như này
=8/15+7/15
=15/15=1
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