Tìm X...
9x[X-49]=219 6xXx5=240
[X-13]x8=184 7x[X:7]=833
8x[168:X]=672 664:[X+7]=8
Tìm x,biết:
A) 8 + ( x - 9)= 125 - 64
B) 5×(x+7) -10 = 8×5
C) 7 × 7 - 7( 13 - 2× x) = 14
D) 320 : (x - 1) = ( 125 - 5 ×5 ) : 4 + 15
E) 240 : ( x -5 ) = 4 × 5 ×5 - 60 : 3
F) 49 × x - 14 × x = 49 × 10 - 70
a. 8 + (x - 9) = 125 - 64
8 + (x - 9) = 61
x - 9 = 53
x = 62
b. 5 x (X + 7) - 10 = 8 x 5
5 x (X + 7) - 10 = 40
5 x (X + 7) = 50
X + 7 = 10
X = 3
a/(-4) x(-3)x(-125)x25x(-8)
b/ (-4)x9x(-125)x25x(-8)
c/ 7x(-25)x(-3)x2x(-4)
d/ [93-(20-7)] : 16
e/ 53-(-51)+(-53)+49
f/ 168-49+(-68)+4
a) \(\left(-4\right)\left(-3\right)\left(-125\right).25.\left(-8\right)=\left[25\left(-4\right)\right]\left[\left(-125\right)\left(-8\right)\right]\left(-3\right)\)
\(=\left(-100\right).1000.\left(-3\right)=300.1000=300000\)
b) \(\left(-4\right).9\left(-125\right).25.\left(-8\right)=\left[25\left(-4\right)\right]\left[\left(-125\right)\left(-8\right)\right].9\)
\(=\left(-100\right).1000.9=\left(-100\right).9000=-900000\)
c) \(7.\left(-25\right)\left(-3\right).2.\left(-4\right)=\left[\left(-25\right)\left(-4\right)\left(-3\right)\right].7.2=-4200\)
d) \(\left[93-\left(20-7\right)\right]\div16=\left(93-13\right)\div16=80\div16=5\)
e) \(53-\left(-51\right)+\left(-53\right)+49=\left(53-53\right)+\left(51+49\right)=100\)
f) \(168-49+\left(-68\right)+4=168-49-68+4=55\)
Bài 2 : Tìm x
8 x ( 168 : x ) = 672
1125 : ( 319 - x ) = 5
Tìm x thuộc Z, biết: 1. 2 |x - 1| - 5(x + 3) - 2(x-7) = |x - 1|- 7x 2. |x - 2| - 5(x - 4) =20 - 5x 3. 4(x - 2) - 3(x + 4 =(-4)(+3)(-125)(+25)(-8) 4. -3(2x - 4) + 7(x-5) = (-67)(1-301) - 301 . 67 5. 7(x - 5) - 4(x+3) = 2(x - 5)+ (13-135 + 49 ) - (13+49) 6. 5(x-3) - 2(x + 1)= 3 + 2(x-1)+(18 + 29) +( 185 - 18 - 29)
Tìm x
A, (x-13)*8=184
B, 7*(x:7)=833
C, 9*(x+5)=729
D, 1200:24-(17-x) =36
a, x-13=184:8
x-13=23
x=23+13
x=36
Vậy x=36
b,x:7=833:7
x:7=119
x=119x7
x=833
Vậy x=833
c, x+5=729:9
x+5=81
x=81-5
x=76
Vậy x=76
d,50-(17-x)=36
17-x=50-36
17-x=14
x=17-14
x=3
Vậy x=3
Hok tốt
Bài 27. Tìm x biết
a. 89 – (73 – x) = 20 b. (x + 7) – 25 = 13 c. 98 – (x + 4) = 20
d. 140 : (x – 8) = 7 e. 4(x + 41) = 400 f. x – [ 42 + (–28)] = –8
g. x + 5 = 20 – (12 – 7) h. (x – 11) = 2.2³ + 20 : 5 i. 4(x – 3) = 7² – 1³.
j. 2x+1.22014 = 22015. k. 2x – 49 = 5.3² ℓ. 3²(x + 14) – 5² = 5.2²
m. 6x + x = 511 : 59 + 31. n. 7x – x = 521 : 519 + 3.2² – 70.
o. 7x – 2x = 617 : 615 + 44 : 11. p. 3x = 9 q. 4x = 64
r. 9x–1 = 9 s. x4 = 16 t. 2x : 25 = 1
u. |x – 2| = 0 v. |x – 5| = 7 – (–3) w. |x – 5| = |–7|
x. |x| – 5 = 3 y. 15 – 2|x| = 13
a) 89-(73-x) = 20
=> 73+x =89-20
=> 73+x=69
=> x=69-73
=> x=-4
b) (x+7)-25=13
=> x+7=13+25
=> x+7=38
=> x=38-7
=> x=31
c) 98-(x+4)=20
=> x+4=98-20
=> x+4=78
=> x=78-4
=> x=73
d) 140:(x-8)=7
=> x-8=140:7
=> x-8=20
=> x=20+8
=> x=28
e) 4(x+41)=400
=> x+41=400:4
=> x+41=100
=> x=100-41
=> x=59
f) x-[42+(-28)]=-8
=> x-14=-8
=> x=-8+14
=> x=6
g) x+5=20-(12-7)
=> x+5=20-5
=> x+5=15
=> x=15-5
=> x=10
h) \(x-11=2.2^3+20:5\)
=> x-11=2.8+4
=> x-11=16+4
=> x-11=20
=> x=20+11
=> x=31
i) \(4\left(x-3\right)=7^2-1^3\)
=> 4(x-3)=49-1
=> 4(x-3)=48
=> x-3=48:4
=> x-3=12
=> x=12+3
=> x=15
* Tìm x, bt:
a.\(\sqrt{\left(2x+3\right)^2}=8\)
b.\(\sqrt{9x}-7\sqrt{x}=8-6\sqrt{x}\)
c.\(\sqrt{9x-9}+1=13\)
a) ⇔ |2x+3| = 8
⇒ \(\left[{}\begin{matrix}2x+3=8\\2x+3=-8\end{matrix}\right.\) ⇔ \(\left[{}\begin{matrix}2x=5\\2x=-11\end{matrix}\right.\) ⇔ \(\left[{}\begin{matrix}x=\dfrac{5}{2}\\x=-\dfrac{11}{2}\end{matrix}\right.\)
Vậy...
b) ĐKXĐ: \(x\ge0\)
\(\Leftrightarrow3\sqrt{x}-7\sqrt{x}+6\sqrt{x}=8\)
\(\Leftrightarrow2\sqrt{x}=8\)
\(\Leftrightarrow\sqrt{x}=4\)
\(\Leftrightarrow x=16\) (Vì \(x\ge0\) )
Vậy x = 16
c) ĐKXĐ: \(x\ge1\)
\(\Leftrightarrow\sqrt{9\left(x-1\right)}=12\)
\(\Leftrightarrow3\sqrt{x-1}=12\)
\(\Leftrightarrow\sqrt{x-1}=4\)
\(\Leftrightarrow x-1=16\)
\(\Leftrightarrow x=17\)(TM)
Vậy x = 17
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= \(\dfrac{1}{3}\)
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
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=\(\dfrac{-23}{7}\)
bài 1 : Tìm x
a) 5 + ( x + 27 ) = 64
b) 64 - ( x - 2 ) = 25
c) 7 - ( x + 5 ) + 14 = 343
d) 5 . x - 25 = 10
e) 4 . ( x - 5 ) - 8 = 48
f) 49 - ( 15 + x ) = 12
g) 49 - 7. ( 13 - x ) = 14
h) 155 - 10. ( x + 1 ) = 55
5 + ( x + 27 ) = 64
( x + 27 ) = 64 - 5 ( x + 27 ) = 59 x = 59 - 27 x = 32a) \(\Rightarrow x+27=59\Rightarrow x=32\)
b) \(\Rightarrow x-2=39\Rightarrow x=41\)
c) \(\Rightarrow x+5=-322\Rightarrow x=-327\)
d) \(\Rightarrow5x=35\Rightarrow x=7\)
e) \(\Rightarrow4\left(x-5\right)=56\Rightarrow x-5=14\Rightarrow x=19\)
f) \(\Rightarrow15+x=37\Rightarrow x=22\)
g) \(\Rightarrow7\left(13-x\right)=35\Rightarrow13-x=5\Rightarrow x=8\)
h) \(\Rightarrow10\left(x+1\right)=100\Rightarrow x+1=10\Rightarrow x=9\)