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a,
\(5^{x+4}-3.5^{x+3}=2.5^{11}\)
\(\Rightarrow5^{x+3}\left(5-3\right)=2.5^{11}\)
\(\Rightarrow5^{x+3}2=2.5^{11}\)
\(\Rightarrow5^{x+3}=5^{11}\)
\(\Rightarrow x+3=11\)
\(\Rightarrow x=8\)
b, (Check lai xem de sai o dau khong nhe)
\(3.5^{x+2}+4.5^{x+3}=19.5^{10}\)
Dat 5x ra ben ngoai
\(\Rightarrow5^x.5^23+5^x:5^{-3}.4\)
\(\Rightarrow5^x\left(5^2.3+5^{-3}.4\right)\)
\(\Rightarrow5^x\left(5^{-3}.5^5.3+5^{-3}.4\right)\)
\(\Rightarrow5^x[5^{-3}\left(5^53+4\right)\)
\(\Rightarrow5^x[5^{-3}\left(3125.3+4\right)\)
\(\Rightarrow5^x\left(5^{-3}\right).9379\)
=> Khong tim duoc gia tri cua x \(\Rightarrow x\in\varnothing\)
a. -3/4 x 12/-5 x (-25/6)=-15/2
b. -2 x -38/21 x -7/4 x (-3/8)=-19/8
c. (11/12: 33/16) x 3/5=4/15
d. 7/23 x [(-8/6)- 45/18]=-7/6
Bài 1:
a; \(\dfrac{7}{8}\) + \(x\) = \(\dfrac{4}{7}\)
\(x\) = \(\dfrac{4}{7}\) - \(\dfrac{7}{8}\)
\(x\) = \(\dfrac{32}{56}\) - \(\dfrac{49}{56}\)
\(x=-\) \(\dfrac{49}{56}\)
Vậy \(x=-\dfrac{49}{56}\)
b; 6 - \(x\) = - \(\dfrac{3}{4}\)
\(x\) = 6 + \(\dfrac{3}{4}\)
\(x\) = \(\dfrac{24}{4}+\dfrac{3}{4}\)
\(x=\dfrac{27}{4}\)
Vậy \(x=\dfrac{27}{4}\)
c; \(\dfrac{1}{-5}\) + \(x\) = \(\dfrac{3}{4}\)
\(x\) = \(\dfrac{3}{4}\) + \(\dfrac{1}{5}\)
\(x=\dfrac{15}{20}\) + \(\dfrac{4}{20}\)
\(x=\dfrac{19}{20}\)
Vậy \(x=\dfrac{19}{20}\)
Bài 1:
d; - 6 - \(x\) = - \(\dfrac{3}{5}\)
\(x\) = - 6 + \(\dfrac{3}{5}\)
\(x=-\dfrac{30}{5}\) + \(\dfrac{3}{5}\)
\(x=-\dfrac{27}{5}\)
Vậy \(x=-\dfrac{27}{5}\)
e; - \(\dfrac{2}{6}\) + \(x\) = \(\dfrac{5}{7}\)
\(x\) = \(\dfrac{5}{7}\) + \(\dfrac{2}{6}\)
\(x\) = \(\dfrac{15}{21}\) + \(\dfrac{1}{3}\)
\(x=\dfrac{15}{21}\) + \(\dfrac{7}{21}\)
\(x=\dfrac{22}{21}\)
Vậy \(x=\dfrac{22}{21}\)
f; - 8 - \(x\) = - \(\dfrac{5}{3}\)
\(x\) = \(-\dfrac{5}{3}\) + 8
\(x\) = \(\dfrac{-5}{3}\) + \(\dfrac{24}{3}\)
\(x\) = \(\dfrac{-19}{3}\)
Vậy \(x=-\dfrac{19}{3}\)
a) x2 + x = 0
=> x( x+ 1 ) = 0
=> x = 0
hoặc x = -1
b) b, (x-1)x+2 = (x-1)x+4
=> x + 2 = x + 4
=> 0x = 2 ( ktm)
Vậy ko có giá trị x nào thoả mãn đk
d) Ta có: x-1/x+5 = 6/7
=>(x-1).7 = (x+5).6
=>7x-7 = 6x+ 30
=> 7x-6x = 7+30
=> x = 37
Vậy x = 37
e, x2/ 6= 24/25
=> x2 . 25 = 6 . 24
⇒x2.25=144⇒x2.25=144
⇒x2=144÷25⇒x2=144÷25
⇒x2=5,76=2,42=(−2,42)⇒x2=5,76=2,42=(−2,42)
⇒x∈{2,4;−2,4}⇒x∈{2,4;−2,4}
Vậy x∈{2,4;−2,4}
a, x + 1/9 - 3/5 = 3/6
x + 1/9 = 3/6 - 3/5
x + 1/9 = -1/10
x = -1/10 - 1/9
x = -19/90
1)\(\frac{1}{x}=\frac{1}{6}+\frac{y}{3}\Rightarrow\frac{1}{x}-\frac{y}{3}=\frac{1}{6}\Rightarrow\frac{3-xy}{3x}=\frac{1}{6}\)
=>1=3-xy và 3x=6
=>x=2; thay vào ta có: 3-2y=1
=>2y=2
=>y=1
a) \(\frac{1}{x}=\frac{1}{6}+\frac{y}{3}\)
\(\Rightarrow\frac{1}{x}=\frac{1+2y}{6}\)
\(\Rightarrow x\left(1+2y\right)=6\)
Ta có bảng sau:
Bạn kẻ bảng ra rồi làm tiếp nhé, các phần còn lại làm tương tự, máy tính lag quá nên không làm cho bạn hết được
a.=> \(\frac{\left(\frac{1}{3}\right).x}{\frac{2}{3}}=\frac{\frac{7}{4}}{\frac{2}{5}}\)
=> \(\frac{1}{3}.x=\frac{7}{4}.\frac{2}{3}:\frac{2}{5}\)
=>\(\frac{1}{3}.x=\frac{35}{12}\)
=> x\(=\frac{35}{12}:\frac{1}{3}\)
Vậy x=\(\frac{35}{4}\).
b. => \(\frac{4,5}{0,3}=\frac{2,25}{0,1.x}\)
=>\(0,1.x=\frac{2,25.0,3}{4,5}\)
=>\(0,1.x=0,15\)
=>\(x=0,15:0,1\)
Vậy x=1,5
c. =>\(\frac{8}{\frac{1}{4}.x}=\frac{2}{0,02}\)
=>\(\frac{1}{4}.x=\frac{8.0,02}{2}\)
=>\(\frac{1}{4}.x=0,08\)
=>\(x=0,08:\frac{1}{4}\)
Vậy x=0,32.
d. =>\(\frac{3}{\frac{9}{4}}=\frac{\frac{3}{4}}{6.x}\)
=>\(3.6x=\frac{9}{4}.\frac{3}{4}\)
=>\(18x=\frac{27}{16}\)
=>\(x=\frac{27}{16}:18\)
Vậy x=\(\frac{3}{32}\)
a) \( - 2{x^2} + 6{x^2} = ( - 2 + 6).{x^2} = 4{x^2}\);
b) \(4{x^3} - 8{x^3} = (4 - 8).{x^3} = - 4{x^3}\);
c) \(3{x^4}( - 6{x^2}) = 3.( - 6).{x^4}.{x^2} = - 18{x^{4 + 2}} = - 18{x^6}\);
d) \(( - 24{x^6}):( - 4{x^3}) = ( - 24: - 4).({x^6}:{x^3}) = 6{x^{6 - 3}} = 6{x^3}\).