(5x-9).7+3=80
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LL
2
NM
29 tháng 9 2023
\(a,210-5\left(x-11\right)=200\\ \Rightarrow5\left(x-11\right)=10\\ \Rightarrow x-11=2\\ \Rightarrow x=13.\\ b,\left(2x+1\right):7=2^2+3^2\\ \Rightarrow\left(2x+1\right):7=4+9\\ \Rightarrow\left(2x+1\right):7=13\\ \Rightarrow2x+1=91\\ \Rightarrow2x=90\\ \Rightarrow x=45.\\ c,450:\left[41-\left(2x-5\right)\right]=3^2.5\\ \Rightarrow450:\left[41-\left(2x-5\right)\right]=45\\ \Rightarrow41-\left(2x-5\right)=10\\ \Rightarrow2x-5=31\\ \Rightarrow2x=36\\ \Rightarrow x=18.\\ d,\left(5x-9\right).7+3=80\\ \Rightarrow\left(5x-9\right).7=77\\ \Rightarrow5x-9=11\\ \Rightarrow5x=20\\ \Rightarrow x=4.\)
29 tháng 9 2023
a) \(210-5\left(x-11\right)=200\)
\(5.\left(x-11\right)=210-200\)
\(5.\left(x-11\right)=10\)
\(x-11=10:5\)
\(x-11=2\)
\(x=2+11\)
\(x=13\)
b) \(\left(2x+1\right):7=2^2+3^2\)
\(\left(2x+1\right):7=13\)
\(2x+1=13.7\)
\(2x=91-1\)
\(2x=90\)
\(x=90:2\)
\(x=45\)
c) \(450:\left[41-\left(2x-5\right)\right]=3^2.5\)
\(450:\left[41-\left(2x-5\right)\right]=45\)
\(\left[41-\left(2x-5\right)\right]=450:45\)
\(\left[41-\left(2x-5\right)\right]=10\)
\(2x-5=41-10\)
\(2x-5=31\)
\(2x=31+5\)
\(2x=36\)
\(x=36:2\)
\(x=18\)
d) \(\left(5x-9\right).7+3=80\)
\(\left(5x-9\right).7=80-3\)
\(5x-9=77:7\)
\(5x-9=11\)
\(5x=11+9\)
\(5x=20\)
\(x=20:5\)
\(x=4\)
T
16 tháng 10 2023
\((5x-39)\cdot7+3=80\\\Rightarrow (5x-39)\cdot7=80-3\\\Rightarrow (5x-39)\cdot7=77\\\Rightarrow 5x-39=77:7\\\Rightarrow 5x-39=11\\\Rightarrow5x=11+39\\\Rightarrow5x=50\\\Rightarrow x=50:5=10\\Vậy:x=10\)
KV
16 tháng 10 2023
(5x - 39).7 + 3 = 80
(5x - 39).7 = 80 - 3
(5x - 39).7 = 77
5x - 39 = 77 : 7
5x - 39 = 11
5x = 11 + 39
5x = 50
x = 50 : 5
x = 10
19 tháng 12 2020
(5x−39).7+3=80(5x-39).7+3=80
⇒(5x−39).7=77⇒(5x-39).7=77
⇒5x−39=11⇒5x-39=11
⇒5x=50⇒5x=50
⇒x=10⇒x=10
Vậyx=10
19 tháng 12 2020
Làm chi tiêt hơn ạ.
(5x - 39 ) . 7 + 3 = 80
( 5x - 39 ) .7 = 80 - 3
( 5x - 39 ) . 7 = 77
5x - 39 = 77:7
5x - 39 = 11
5x = 39 + 11
5x = 50
x = 50 : 5
x = 10
Vậy x = 10
19 tháng 2 2022
a: \(\Leftrightarrow7\left(7-3x\right)+12\left(5x+2\right)=84\left(x+13\right)\)
\(\Leftrightarrow49-21x+60x+24=84x+1092\)
\(\Leftrightarrow39x-84x=1092-73\)
=>-45x=1019
hay x=-1019/45
b: \(\Leftrightarrow21\left(x+3\right)-14=4\left(5x+9\right)-7\left(7x-9\right)\)
=>21x+63-14=20x+36-49x+63
=>21x+49=-29x+99
=>50x=50
hay x=1
c: \(\Leftrightarrow7\left(2x+1\right)-3\left(5x+2\right)=21x+63\)
=>14x+7-15x-6-21x-63=0
=>-22x-64=0
hay x=-32/11
d: \(\Leftrightarrow35\left(2x-3\right)-15\left(2x+3\right)=21\left(4x+3\right)-17\cdot105\)
=>70x-105-30x-45=84x+63-1785
=>40x-150-84x+1722=0
=>-44x+1572=0
hay x=393/11
TT
Tìm x biết :
a) 3(5/3x-7)-2(1.5x+6)-(5-x)(x+4)=80+x^2
b) 4/5x^2(x/3-1/2)-(1/5x-2/3)(4x^2/3+1)=22/45x^2
1
YN
10 tháng 3 2022
`Answer:`
\(3\left(\frac{5}{3}x-7\right)-2\left(1.5x+6\right)-\left(5-x\right)\left(x+4\right)=80+x^2\)
\(\Leftrightarrow3\left(\frac{5x}{3}-7\right)-2\left(5x+6\right)-\left(5-x\right)\left(x+4\right)=80+x^2\)
\(\Leftrightarrow5x-21-10x-12-5x-20+x^2+4x=80+x^2\)
\(\Leftrightarrow5x-21-10x-12-5x-20+4x=80\)
\(\Leftrightarrow-6x-53=80\)
\(\Leftrightarrow-6x=133\)
\(\Leftrightarrow x=-\frac{133}{6}\)
\(\frac{4}{5}x^2\left(\frac{x}{3}-\frac{1}{2}\right)-\left(\frac{1}{5}x-\frac{2}{3}\right)\left(4\frac{x^2}{3}+1\right)=\frac{22}{45}x^2\)
\(\Leftrightarrow36x^2\left(\frac{x}{3}-\frac{1}{2}\right)-45\left(\frac{x}{5}-\frac{2}{3}\right)\left(\frac{4x^2}{3}+1\right)=22x^2\)
\(\Leftrightarrow12x^3-18x^2-12x^3-9x+40x^2+30=22x^2\)
\(\Leftrightarrow22x^2-9x+30=22x^2\)
\(\Leftrightarrow-9x+30=0\)
\(\Leftrightarrow-9x=-30\)
\(\Leftrightarrow x=\frac{10}{3}\)
TT
Tìm x biết :
a) 3(5/3x-7)-2(1.5x+6)-(5-x)(x+4)=80+x^2
b) 4/5x^2(x/3-1/2)-(1/5x-2/3)(4x^2/3+1)=22/45x^2
0
DH
7 tháng 7 2017
a, \(3.\left(\dfrac{5}{3}x-7\right)-2\left(1,5x+6\right)-\left(5-x\right)\left(x+4\right)=80+x^2\)
\(\Rightarrow5x-21-3x-12-\left(5x+20-x^2-4x\right)-x^2=80\)
\(\Rightarrow5x-21-3x-12-5x-20+x^2+4x-x^2=80\)
\(\Rightarrow5x-3x-5x+4x+x^2-x^2=80+21+12+20\)
\(\Rightarrow x=133\)
Câu b tương tự! Cứ tách ra!
Q
7 tháng 7 2017
a) \(3\left(\dfrac{5}{3}x-7\right)-2\left(1,5x+6\right)-\left(5-x\right)\left(x+4\right)=80+x^2\) (1)
\(\Leftrightarrow\left(5x-21\right)-\left(3x+12\right)-\left(5x+20-x^2-4x\right)=80+x^2\)
\(\Leftrightarrow5x-21-3x-12-5x-20+x^2+4x=80+x^2\)
\(\Leftrightarrow x-53+x^2=80+x^2\)
\(\Leftrightarrow x+x^2-x^2=80+53\)
\(\Leftrightarrow x=133\)
Vậy tập nghiệm phương trình (1) là \(S=\left\{133\right\}\)
b) chưa rõ đề.
( 5x - 9 ) . 7 + 3 = 80
( 5x - 9 ) . 7 = 80 - 3 = 77
5x - 9 = 77 : 7 = 11
5x = 11 + 9 = 20
x = 20 : 5 = 4
(5x-9).7+3 =80
=>(5x-9).7=77
=>5x-9=11
=>5x=20
=>x=4