Tìm x biết
a) 12 - /x - 3 / = 5x + 8
b) 3 - 0,2x / 5 = 7/15 + 1,4x
Tìm x, biết:
a) \(12-\left|x-3\right|=5x+8\)
b) \(\left(\sqrt{x}+3\right)^{10}=1024.125^2.25^2\)
c) \(\dfrac{3-0,2x}{5}=\dfrac{7}{15}+1,4x\)
d) \(\left(\dfrac{64}{27}\right)^x=\dfrac{4.5^9.7^{10}-5^{11}.7^9}{35^9.4}\)
Các bn giúp mk nhanh nha. Tối nay mk phải nộp cho thầy r. Mk sẽ tick cho.
a: \(\Leftrightarrow\left|x-3\right|=12-5x-8=-5x+4\)
\(\Leftrightarrow\left\{{}\begin{matrix}x< =\dfrac{4}{5}\\\left(-5x+4\right)^2=\left(x-3\right)^2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x< =\dfrac{4}{5}\\\left(5x-4-x+3\right)\left(5x-4+x-3\right)=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x< =\dfrac{4}{5}\\\left(4x-1\right)\left(6x-7\right)=0\end{matrix}\right.\Leftrightarrow x=\dfrac{1}{4}\)
b: \(\left(\sqrt{x}+3\right)^{10}=1024\cdot125^2\cdot25^2\)
\(\Leftrightarrow\left(\sqrt{x}+3\right)^{10}=2^{10}\cdot5^6\cdot5^4=10^{10}\)
\(\Leftrightarrow\sqrt{x}+3=10\)
hay x=49
c: \(\dfrac{3-0.2x}{5}=\dfrac{7}{15}+1.4x\)
\(\Leftrightarrow\dfrac{9-0.6x}{15}=\dfrac{7}{15}+\dfrac{21x}{15}\)
=>21x+7=9-0,6x
=>21,6x=-2
hay x=-5/54
d: \(\Leftrightarrow\left(\dfrac{4}{3}\right)^{3x}=\dfrac{5^9\cdot7^9\left(4\cdot7-5^2\right)}{5^9\cdot7^9\cdot4}\)
\(\Leftrightarrow\left(\dfrac{4}{3}\right)^{3x}=\dfrac{28-25}{4}=\dfrac{3}{4}\)
=>3x=-1
hay x=-1/3
tìm x biết
a, 4(18-5x) - 12(3x-7) = 15(2x - 16) - 6(x + 14)
b, 5(3x +5) - 4(2x - 3) = 5x + 3 (2x +12) +1
a) \(4\left(18-5x\right)-12\left(3x-7\right)=15\left(2x-16\right)-6\left(x+14\right)\)
\(\Rightarrow72-20x-36x-84=30x-240-6x+84\)
\(\Rightarrow\left(72-84\right)-\left(20x+36x\right)=\left(30x-6x\right)-240+84\)
\(\Rightarrow-12-56=24x-56x\)
\(\Rightarrow-12+156=24x+56x\)
\(\Rightarrow144=80x\)
\(\Rightarrow x=144:80\)
\(\Rightarrow x=\frac{9}{5}\)
b) \(5\left(3x+5\right)-4\left(2x-3\right)=5x+3\left(2x+12\right)+1\)
\(\Rightarrow15x+25-8x+12=5x+6x+36+1\)
\(\Rightarrow15x+25-8x+12-5x-6x-36-1=0\)
\(\Rightarrow-4x=0\)
\(\Rightarrow-4.0\)
\(\Rightarrow x=0\)
a) 4(18 - 5x) - 12(3x - 7) = 15(2x - 16) - 6(x +14)
<=> 72 - 20x - 36x + 84 = 30x - 240 - 6x - 84
<=> -20x - 36x - 30x + 6x = -72 - 84 - 240 - 84
<=> -80x = -480
<=> x = 6
b) 5(3x + 5) - 4(2x - 3) = 5x + 3(2x + 12) + 1
<=> 15x + 25 - 8x + 12 = 5x + 6x + 36 + 1
<=> 15x - 8x - 5x - 6x = -25 - 12 + 36 + 1
<=> -4x = 0
<=> x = 0
CTV sai dấu rồi kìa '-'
Tìm x biết
a) 2/5 -2/5x +1/3 =x-7/15
b)x-x/3 =3/57 :-12/19
a) \(\frac{2}{5}-\frac{2}{5}x+\frac{1}{3}=x-\frac{7}{15}\)
\(\Leftrightarrow\frac{11}{15}-\frac{2x}{5}=x-\frac{7}{15}\)
\(\Leftrightarrow\frac{2x}{5}=x-\frac{7}{15}-\frac{11}{15}\)
\(\Leftrightarrow-\frac{2x}{5}=x-\frac{5}{6}\)
\(\Leftrightarrow-\frac{2x}{5}=x.5-\frac{5}{6}.5\)
\(\Leftrightarrow-2x=5x-6\)
\(\Leftrightarrow-2x=-5x-6-5x\)
\(\Leftrightarrow-7x=-6\)
\(\Rightarrow x=\frac{6}{7}\)
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
\(\dfrac{-3}{4}x\dfrac{4}{7}+\dfrac{-3}{5}x\dfrac{3}{7}-\dfrac{2}{5}\)
\(\left(\dfrac{3}{4}x\dfrac{5}{6}-\dfrac{7}{12}\right)x\left(\dfrac{-12}{7}\right)\)
\(1,4x\dfrac{15}{19}x\left(\dfrac{4}{5}x\dfrac{-2}{3}\right)+\dfrac{7}{15}\)
Tính nha
a: \(=\dfrac{-3}{7}+\dfrac{-9}{35}-\dfrac{2}{5}\)
\(=\dfrac{-15-9-14}{35}=\dfrac{-38}{35}\)
b: \(=\left(\dfrac{15}{24}-\dfrac{7}{12}\right)\cdot\dfrac{-12}{7}\)
\(=\dfrac{15-14}{24}\cdot\dfrac{-12}{7}=\dfrac{1}{24}\cdot\dfrac{-12}{7}=\dfrac{-1}{14}\)
c: \(=\dfrac{7}{5}\cdot\dfrac{15}{19}\cdot\dfrac{-8}{15}+\dfrac{7}{15}\)
\(=\dfrac{-56}{95}+\dfrac{7}{15}\)
\(=\dfrac{-7}{57}\)
Tìm x, biết: a) 121-(115+x)= 3x-(25-9-5x)-8
b)2x+2.3x+1.5x = 10800
c) (3|x-1/2) . (8/15-1/5)+2/3-1
d) x+1/2022 + x+2/2021= x+3/2020 + x+4/2019
\(a,121-\left(115+x\right)=3x-\left(25-9-5x\right)-8\\ 121-115-x=3x-25+9+5x-8\\ 6-x=8x-24\\ 8x+x=-24-6\\ 9x=-30\\ x=-\dfrac{30}{9}=-\dfrac{10}{3}\\ ----\\ b,2^{x+2}.3^{x+1}.5^x=10800\\ \left(2.3.5\right)^x.2^2.3=10800\\ 30^x.12=10800\\ 30^x=\dfrac{10800}{12}=900=30^2\\ Vậy:x=2\)