tìm x biết
a, 1/2 - 3/4x > 0,25
b, 2x - 0,75 < 1/2
c, 0,5 - 3x > 4/5
Những câu hỏi liên quan
tìm x ,biết:
a,3x -0,75 =-1,2
b,2/3/5 : (2x-1/2)=1,3
c,3/4x -5/6=7/12x-5/4
a,3x-0,75=-1,2
3x=-1,2+-0,75
3x=-9/20
x=-9/20:3
x=-3/20
kl:....
b,2/3/5:(2x-1/2)=1,3
2/3/5??????
c,3/4x-5/6=7/12x-5/4
3/4x-7/12x=-5/4+5/6
9/12x-7/12x=-15/12+10/12
2/12x=-5/12
2:12x=-5/12
12x=2:-5/12
12x=-24/5
x=-24/5:12
x=-2/5
kl:....
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tìm x biết
a) (6x-3) (2x+4) + (4x-1) (5-3x) = -21
b) 6x (3x+5) - 2x (9x-2) + (17-x) (x-1) + x (x-18) =0
c) (15-2x) (4x+1) - (13-4x) (2x-3) - (x-1) (x+2) + x2=52
d) (8x-3) (3x+2) - (4x+7) (x+4) = (2x+1) (5x-1) - 33
Rút gọn hết ta được :
a/ 41x - 17 = -21
=> 41x = -4 => x = 4/41
b/ 34x - 17 = 0
=> 34x = 17
=> x = 17/34 = 1/2
c/ 19x + 56 = 52
=> 19x = -4
=> x = -4/19
d/ 20x2 - 16x - 34 = 10x2 + 3x - 34
=> 10x2 - 19x = 0
=> x(10x - 19) = 0
=> x = 0
hoặc 10x - 19 = 0 => 10x = 19 => x = 19/10
Vậy x = 0 ; x = 19/10
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Rút gọn hết ta được :
a/ 41x - 17 = -21
=> 41x = -4 => x = 4/41
b/ 34x - 17 = 0
=> 34x = 17
=> x = 17/34 = 1/2
c/ 19x + 56 = 52
=> 19x = -4
=> x = -4/19
d/ 20x 2 - 16x - 34 = 10x 2 + 3x - 34
=> 10x 2 - 19x = 0
=> x(10x - 19) = 0
=> x = 0 hoặc 10x - 19 = 0
=> 10x = 19
=> x = 19/10
Vậy x = 0 ; x = 19/10
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a) ( 6x - 3 ) ( 2x + 4 ) + ( 4x - 1 ) ( 5 - 3x ) = -21
<=> 12x2 + 24x - 6x - 12 + 20x - 12x2 - 5 + 3x = -21
<=> 41x = -21 + 12 + 5
<=> 41x = -4
<=> x = -4/41
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Xem thêm câu trả lời
Tìm x
a 5(2x-3)-4(5x-7)=19-2(x+11)
b 7(4x+3)-4(x-1)=15(x+0,75)+7
c 3x-2,42+0,8x=3,38-0,2x
d (x-1)2+(x+3)2=2(x-2)(x+1)+38
e 5(x2-2x-1)+2(3x-2)=5(x+1)2
Tìm x
a 5(2x-3)-4(5x-7)=19-2(x+11)
b 7(4x+3)-4(x-1)=15(x+0,75)+7
c 3x-2,42+0,8x=3,38-0,2x
d (x-1)2+(x+3)2=2(x-2)(x+1)+38
e 5(x2-2x-1)+2(3x-2)=5(x+1)2
Tìm x
a 5(2x-3)-4(5x-7)=19-2(x+11)
b 7(4x+3)-4(x-1)=15(x+0,75)+7
c 3x-2,42+0,8x=3,38-0,2x
d (x-1)2+(x+3)2=2(x-2)(x+1)+38
e 5(x2-2x-1)+2(3x-2)=5(x+1)2
Tìm x
a 5(2x-3)-4(5x-7)=19-2(x+11)
b 7(4x+3)-4(x-1)=15(x+0,75)+7
c 3x-2,42+0,8x=3,38-0,2x
d (x-1)2+(x+3)2=2(x-2)(x+1)+38
e 5(x2-2x-1)+2(3x-2)=5(x+1)2
1) Giải các phương trình sau:
a) 5(2x-3)-4(5x-7)=19-2(x+11)
b) 4(x+3)-7x+17=8(5x-1)+166
c) 17-14(x+1)=13-4(x+1)-5(x-3)
d) 5x+3,5+(3x-4)=7x-3(x-0,5)
e) 7(4x+3)-4(x-1)=15(x+0,75)+7
f) 3x+2,42+o,8x=3,38-0,2x
\(\text{a) 5(2x-3)-4(5x-7)=19-2(x+11)}\)
\(10x-15-20x+28=19-2x-22\)
\(10x-20x+2x=19-22-28+15\)
\(-8x=-16\)
\(\Rightarrow x=2\)
\(\text{b) 4(x+3)-7x+17=8(5x-1)+166}\)
\(4x+12-7x+17=40x-8+166\)
\(4x-7x-40x=-8+166-17-12\)
\(-43x=129\)
\(x=-3\)
\(\text{c) 17-14(x+1)=13-4(x+1)-5(x-3)}\)
\(17-14x+14=13-4x-4-5x+15\)
\(-14x+4x+5x=13-4+15-14-17\)
\(-5x=-7\)
\(x=\frac{7}{5}\)
\(\text{d) 5x+3,5+(3x-4)=7x-3(x-0,5)}\)
\(5x+3,5+3x-4=7x-3x+1,5\)
\(5x+3x-7x+3x=1,5-3,5\)
\(x=-2\)
\(\text{e) 7(4x+3)-4(x-1)=15(x+0,75)+7}\)
\(28x+21-4x+4=15x+11,25+7\)
\(28x-4x-15x=11,25+7-4-21\)
\(9x=\frac{-27}{4}\)
\(x=\frac{-3}{4}\)
\(\text{f) 3x+2,42+o,8x=3,38-0,2x}\)
\(3x+0,8x+0,2x=3,38-2,42\)
\(4x=\frac{24}{25}\)
\(x=\frac{6}{25}\)
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Bài 1: Tìm x : A) 25%x+4x=35-0,75x
B) 3/4.(x-2) - 1/2.(6-2x)=1/6x + 5
C) -1/2.(3x+5) - 2/3.(9-6x)= 3/5.(x-10) - 3
D) (1/4x - 1,5) + (5/6x-3) - (5/8x-0,5)= -4,5
Tim x:
a) (2x - 1)^3 = 8
b) (x - 1)^x+2 = (x - 1)^x + 4
c) 3^x - 1 + 5 . 3^3x -1 =162
d) x - 0,75 : 0,5 = (1/2)^3 .(-1)^6
a, (2x-1)3=8
2x-1=2
2x=2+1
2x=3
x=1,5
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a, \(\left(2x-1\right)^3=8\)
\(\Leftrightarrow\left(2x-1\right)^3=2^3\)
\(\Leftrightarrow2x-1=2\Leftrightarrow2x=3\Leftrightarrow x=\frac{3}{2}\)
b, \(\left(x-1\right)^x+2=\left(x-1\right)^x+4\)
\(\Leftrightarrow\left(x-1\right)^x+2-\left(x-1\right)^x-4=0\)
\(\Leftrightarrow-2\ne0\)=> vô nghiệm
c, \(3^x-1+5.3^{3x}-1=162\)
Đề sai.