a, x-2=2 hoặc x-2=-2
<=>x=4 <=>x=0
b,x+1=2 hoặc x+1=-2
<=>x=-1 x=-3
c,x-4/5=3/4 hoặc x-4/5=-3/4
<=>x=31/20 <=>x=1/20
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a,2^12.3^54^6.81/(2^2.3)^6+8^4.3^5
b, 4.(-1/2)^3-2.(-1/2)^2+3.(-1/2)+1
c, 5x-7=3x+9
d, 5x-|9-7x|=3
e, -5+|3x-1|+6=|-4|
g, (x-1)^2=(x-1)^4
h, 5^-1.25=125
i, |x+1|+|x+2|+|x+3|=4x
BÀI 1:Tính bằng cách hợp lý nhất: | BÀI 2:Tìm x biết:
a) 1frac{4}{23}+frac{5}{21}-frac{4}{23}+0,5+frac{16}{21} ; | a) |x+5|-69
b) 23frac{1}{4}.frac{7}{5}-13frac{1}{4}:frac{5}{7} ; | b) left(x-1right)^225
c) frac{2^4.2^6}{left(2^5right)^2}-frac{2^5.15^3}{6^3.10^2} |
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BÀI 1:Tính bằng cách hợp lý nhất: | BÀI 2:Tìm x biết:
a) 1\(\frac{4}{23}\)+\(\frac{5}{21}\)-\(\frac{4}{23}\)+0,5+\(\frac{16}{21}\) ; | a) |x+5|-6=9
b) \(23\frac{1}{4}\).\(\frac{7}{5}\)-13\(\frac{1}{4}\):\(\frac{5}{7}\) ; | b) \(\left(x-1\right)^2=25\)
c) \(\frac{2^4.2^6}{\left(2^5\right)^2}-\frac{2^5.15^3}{6^3.10^2}\) |
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BÀI 3:Tìm x biết:
a) \(\frac{x}{12}-\frac{5}{6}=\frac{1}{12}\) e) \(1\frac{1}{2}.x-4=0,5\)
b) \(\frac{2}{3}-1\frac{4}{15}x=\frac{-3}{5}\) f) 2x-1 =16
c) -23 +0.5x=1.5 g) (x-1)2 =25
d) \(\frac{\left(-3\right)^x}{81}=27\) h) |2x-1|=5
Chung minh:
a/ \(5^5-5^4+5^3⋮7\)
b/ \(7^6+7^5-7^4⋮11\)
c/ \(3^{x+2}-2^{x+3}+3^x-2^{x+1}⋮10\)
d/ \(3^{x+3}+3^{x+1}+2^{x+3}+2^{x+2}⋮6\)
Tìm x, biết
a.dfrac{2}{3}x-dfrac{1}{2}x (dfrac{-7}{12}) . dfrac{7}{5}
b.(dfrac{1}{5} - dfrac{3}{2}x)^2 dfrac{9}{4}
c. (1,25 - dfrac{4}{5}x)^3 -125
d. 2^x + 2^{x+4} 544
e.dfrac{3}{4}x - 4,5+ dfrac{4}{5}x 3
g. left|3x-2right| left|2x-3right|
h.(x2 -4)sqrt{x} 0
i. (dfrac{1}{3}x - 4 )2 dfrac{16}{25}
j.4x2 -1 0
k.2x2+0,82 1
l.dfrac{5}{12}sqrt{x} - dfrac{1}{6} dfrac{1}{3}
m.(sqrt{x-1} + 5)(x-6sqrt{x} 0
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Tìm x, biết
a.\(\dfrac{2}{3}\)x-\(\dfrac{1}{2}\)x = (\(\dfrac{-7}{12}\)) . \(\dfrac{7}{5}\)
b.(\(\dfrac{1}{5}\) - \(\dfrac{3}{2}\)x)\(^2\) = \(\dfrac{9}{4}\)
c. (1,25 - \(\dfrac{4}{5}\)x)\(^3\) = -125
d. 2\(^x\) + 2\(^{x+4}\) = 544
e.\(\dfrac{3}{4}\)x - 4,5+ \(\dfrac{4}{5}\)x = 3
g. \(\left|3x-2\right|\) =\(\left|2x-3\right|\)
h.(x2 -4)\(\sqrt{x}\) = 0
i. (\(\dfrac{1}{3}\)x - 4 )2 = \(\dfrac{16}{25}\)
j.4x2 -1 = 0
k.2x2+0,82 =1
l.\(\dfrac{5}{12}\)\(\sqrt{x}\) - \(\dfrac{1}{6}\) = \(\dfrac{1}{3}\)
m.(\(\sqrt{x-1}\) + 5)(x-6\(\sqrt{x}\) = 0
Tìm x, sao cho:
a) 1 - 2*x < 7
b) (x - 1)*(x - 2) > 0
c) ( x - 2)^2*(x + 1)*(x - 4) < 0
d) x^2*(x - 3) / x - 9 < 0
e) 5/x < 1
Bài 1: Tìm x, biết
a,\(\dfrac{1}{2}+\dfrac{2}{3}.x=\dfrac{4}{5}\)
b,\(x+\dfrac{1}{4}=\dfrac{4}{3}\)
c,\(\dfrac{3}{5}x-\dfrac{1}{2}=-\dfrac{1}{7}\)
d,\(|x-\dfrac{4}{5}|=\dfrac{3}{4}\)
e,\(\dfrac{1}{2}-lxl=\dfrac{1}{3}\)
Tìm x biết
a)left(3x+dfrac{1}{3}right)left(x-dfrac{1}{2}right)0
b)left(x-dfrac{3}{2}right)left(2x+1right)0
c)left(2-xright)left(dfrac{4}{5}-xright) 0
d)left(x-dfrac{4}{7}right):left(x+dfrac{1}{2}right)0
e)2left(x+1right)-dfrac{1}{3}.left(x-1right)dfrac{2}{3}
k)left|4x-0,2right|0,2
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Tìm x biết
a)\(\left(3x+\dfrac{1}{3}\right)\left(x-\dfrac{1}{2}\right)=0\)
b)\(\left(x-\dfrac{3}{2}\right)\left(2x+1\right)>0\)
c)\(\left(2-x\right)\left(\dfrac{4}{5}-x\right)< 0\)
d)\(\left(x-\dfrac{4}{7}\right):\left(x+\dfrac{1}{2}\right)>0\)
e)\(2\left(x+1\right)-\dfrac{1}{3}.\left(x-1\right)=\dfrac{2}{3}\)
k)\(\left|4x-0,2\right|=0,2\)
Tìm x biết:
a)\(3^{X+2}-3^{X+1}=162\)
b)\(5^{X+1}+5^{X+2}=3750\)
c)7\(^{4-x}-7^{3-x}=294\)
d)11\(^x-11^{x-1}=1452\)
e)\(2^x+2^{x-2}=40\)
1. tính
a) 3/7 + ( -5/2) + (-3/5)
b) -8/18 - 15/27
c) 4/5 - (-2/7) - 7/10
2. tìm x
a) x+1/4=4/3
b) -x - 2/3 = -6/7
c) x2 = 16
d) 2/3 + 5/3 x = 5/7
3. Cho ∆ ABC vuông tại A, có AB = AC gọi K là trung điểm của cạnh BC
a) CM: ∆AKB= ∆AKC
b) CM: AK vuông góc BC