Tìm x
a)346.124 - 7.(2x - 1 ) = 346
b)\(\frac{4}{3}\)+ 2.(5+7x)=115:5
Những câu hỏi liên quan
a.346.124-7.(2x-1)=346
b.4/3+2,(5+7x)=115:5
a:\(\Leftrightarrow7\left(2x-1\right)=346\cdot124-346=42558\)
=>2x-1=42558/7
=>2x=42565/7
hay x=42565/14
b: \(\Leftrightarrow2\left(7x+5\right)=23-\dfrac{4}{3}=\dfrac{65}{3}\)
=>7x+5=65/6
=>7x=35/6
hay x=5/6
Đúng 0
Bình luận (0)
Tim x
a.346.124-7.(2x-1)=346
b.4/3+2.(5+7x)=115:5
a) 7(2x-1)=(346.124)-346
14x-7=42558
14x=42551
x=42551/14
b) 4/3+2(5+7x)=23
2(5+7x)=65/3
5+7x=65/6
7x=35/6
x=5/6
Đúng 0
Bình luận (0)
a) 346.124-7.(2x-1)=343
346.124-14x+7=343
42904-14x+7=343
-14x=343-42904-7
-14x=-42568
x=\(\dfrac{-42568}{-14}\)=\(\dfrac{42568}{14}\)=3,04
vậy x = 3,04
b)\(\dfrac{4}{3}\)+2(5+7x)=115:5
\(\dfrac{4}{3}\)+10+14x=23
14x=23-10-\(\dfrac{4}{3}\)
14x= \(\dfrac{35}{3}\)
x=\(\dfrac{35}{3}\):14
x=\(\dfrac{35}{42}\)=\(\dfrac{5}{6}\)
Đúng 0
Bình luận (0)
Tìm x
a)346.124 - 7.(2x - 1 ) = 346
b)4/3 + 2.(5+7x)=115:5
Tìm x :
346 . 124 - 7 . ( 2x - 1 ) = 346
7 . ( 2x - 1 ) = ( 346 . 124 ) - 346
7. ( 2x - 1 ) = 346 . 123
7 . 2x - 7 .1 = 42558
7 . 2x = 42558 - 7
7.2. x = 42551
14 . x = 42551
=> x = \(\dfrac{42551}{14}\)
Vậy : x = \(\dfrac{42551}{14}\)
b) \(\dfrac{4}{3}\) +2 . ( 5 + 7x ) = 115 : 5
\(\dfrac{4}{3}\) + 2. 5 + 2 . 7.x = 23
\(\dfrac{4}{3}\) + 10 + 14 . x = 23
\(\dfrac{4}{3}\) + 24 . x = 23
=> \(\dfrac{76}{3}\) . x = 23
=> x = 23 : \(\dfrac{76}{3}\)
=> x = \(\dfrac{69}{76}\)
Vậy x = \(\dfrac{69}{76}\)
Đúng 0
Bình luận (0)
Tìm x
a) 6x(5x + 3) + 3x(1 – 10x) = 7 b) (3x – 3)(5 – 21x) + (7x + 4)(9x – 5) = 44
c) (x + 1)(x + 2)(x + 5) – x2(x + 8) = 27
d) 5x(12x + 7) – 3x(20x – 5) = - 100
e) 0,6x(x – 0,5) – 0,3x(2x + 1,3) = 0,138
a) 6x(5x + 3) + 3x(1 – 10x) = 7
⇒ 30x2+18x+3x-30x2=7
⇒21x=7
⇒x=\(\dfrac{7}{21}\)
⇒x= \(\dfrac{1}{3}\)
Đúng 1
Bình luận (0)
b) (3x – 3)(5 – 21x) + (7x + 4)(9x – 5) = 44
⇒15x-63x2-15+63x + 63x2-35x+36x-20=44
⇒79x-35=44
⇒79x=44+35
⇒79x=79
⇒x=1
Đúng 1
Bình luận (0)
d) 5x(12x + 7) – 3x(20x – 5) = - 100
⇒60x2+35x-60x2+15=-100
⇒35x+15=-100
⇒35x=-100-15
⇒35x=-115
⇒x=\(\dfrac{-115}{35}\)
⇒x=\(\dfrac{-23}{7}\)
Đúng 1
Bình luận (0)
Xem thêm câu trả lời
Tìm x
a,(7x+4)^2-(7x+4)(7x-4)=0
b, 5( x + 3 )( x - 3 ) + ( 2x + 3 )^2+(x-6)^=10
c, (x + 1)^3 + (x – 2)^3 – 2x^2 (x – 1,5) = 3
d,( x + 2)(x^2 – 2x + 4)(x – 2)(x^2 + 2x + 4) = – 65
e, 4x^2 + 4x – 5 = 2
f,16x^2 – 9(x + 1)^2 = 0
Các bạn giúp mình vs mai mình phải nộp rùii
f: Ta có: \(16x^2-9\left(x+1\right)^2=0\)
\(\Leftrightarrow\left(4x-3x-3\right)\left(4x+3x+3\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(7x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-\dfrac{3}{7}\end{matrix}\right.\)
Đúng 0
Bình luận (0)
Tìm x, biết :
\(a.\frac{7^{x+2}+7^{x+1}+7x}{57}=\frac{5^{2x}+5^{2x+1}+5^{2x+3}}{131}\)
\(b.\left(4x-3\right)^4=\left(4x-3\right)^2\)
\(\frac{7^{x+2}+7^{x+1}+7x}{57}=\frac{5^{2x}+5^{2x+1}+5^{2x+3}}{131}\)
\(\Rightarrow\frac{7x\left(7^2+7^1+1\right)}{57}=\frac{5^{2x}\left(1+5^1+5^3\right)}{131}\)
\(\Rightarrow\frac{7x\left(49+7+1\right)}{57}=\frac{5^{2x}\left(1+5+125\right)}{131}\)
\(\Rightarrow\frac{7x.57}{57}=\frac{5^{2x}.131}{131}\)
\(\Rightarrow7x=25x\)
\(\Rightarrow x=0\)
\(\left(4x-3\right)^4=\left(4x-3\right)^2\)
\(\Rightarrow\left(4x-3\right)^4-\left(4x-3\right)^2=0\)
\(\Rightarrow\left(4x-3\right)^2\left[\left(4x-3\right)^2-1\right]=0\)
\(\Leftrightarrow\hept{\begin{cases}\left(4x-3\right)^2=0\\\left(4x-3\right)^2=1\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}4x-3=0\\4x-3=-1\\4x-3=1\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x=\frac{3}{4}\\x=\frac{1}{2}\\x=1\end{cases}}\)
Bài mình làm sai à hay sao mà t]ick sai thế???
Xem thêm câu trả lời
tìm x
a) 4/7x - 2/3 = 1/5
b) 4/5 + 5/7 :x = 1/6
giúp mình lẹ nha
a, \(\dfrac{4x}{7}=\dfrac{1}{5}+\dfrac{2}{3}=\dfrac{3+10}{15}=\dfrac{13}{15}\Rightarrow60x=91\Leftrightarrow x=\dfrac{91}{60}\)
b, \(\dfrac{5}{7}:x=\dfrac{1}{6}+\dfrac{4}{5}=\dfrac{5+24}{30}=\dfrac{29}{30}\Leftrightarrow x=\dfrac{5}{7}:\dfrac{29}{30}=\dfrac{150}{203}\)
Đúng 0
Bình luận (0)
tìm x trong các tỉ lệ thức sau :
\(a. \frac{x+5}{x+9}=\frac{x+4}{x+3}\)
\(b. \frac{2x-7}{2x+11}=\frac{5-3x}{4-2x}\)
\(c. \frac{3x+5}{-3x+11}=\frac{7x-5}{7-7x}\)
\(d. \frac{5x-3}{x+1}=\frac{5x-7}{x-1}\)
Tìm x:\(a,\frac{6x-5}{-7}=\frac{5x-3}{-5}\\ b,\frac{12-7x}{-13}=\frac{4-3x}{-5}\\ c,\frac{2x+4}{7}=\frac{4x-2}{15}\)
a) \(\frac{6x-5}{-7}=\frac{5x-3}{-5}\)
=> -5(6x - 5) = -7(5x - 3)
=> -30x + 25 = -35x + 21
=> -30x + 25 + 35x - 21 = 0
=> (-30x + 35x) + (25 - 21) = 0
=> 5x + 4 = 0
=> 5x = -4
=> x = -4/5
b) \(\frac{12-7x}{-13}=\frac{4-3x}{-5}\)
=> -5(12 - 7x) = -13(4 - 3x)
=> -60 + 35x = -52 + 39x
=> -60 + 35x + 52 - 39x = 0
=> (-60 + 52) + (35x - 39x) = 0
=> -8 - 4x = 0
=> -8 = 4x
=> x = -2
c) \(\frac{2x+4}{7}=\frac{4x-2}{15}\)
=> 15(2x + 4) = 7(4x - 2)
=> 30x + 60 = 28x - 14
=> 30x + 60 - 28x + 14 = 0
=> 2x + 74 = 0
=> 2x = -74
=> x = -37