(x+4) +(x+7) + .........+ (x+ 28 ) = 156
(x+2) + (x+4) + ( x +6 ) +........+ (x+ 1996 ) = 998000
11x (x-6 ) = 4 x x +11
x+2 x x + 3 x x +......+ 10 x x =165
1/ -7(5-x)-2(x-10)=15
2/ 4(x-5)-3(x+7)= -19
3/ 4(2-x)+3(x-5)=14
4/ 7(x-9)-5(6-x)=-6+11x
5/ -7(3x-5)+2(7x-14)=28
6/ 5(4-x)-7(-x+2)=4-9+3
7/ 4x-5(-3+x)=7
8/ 5(x-7)+10(3-x)=20
9/ 7(5-x)+5(x-2)=15
1/ Suy ra: -35 + 7x - 2x + 20 = 15
5x - 15 = 15
5x = 30
x = 6
2/ Suy ra: 4x - 20 - 3x - 21 = -19
x - 41 = -19
x = 22
3/ Suy ra: 8 - 4x + 3x - 15 = 14
-7 -x = 14
x = -7 -14
x = -21
4/ Suy ra: 7x - 63 - 30 + 5x = -6 + 11x
7x + 5x - 11x = -6 +63 + 30
x = 87
5/ Suy ra: -21x +35 + 14x - 28 = 28
-21x + 14x = 28 +28 - 35
-7x = 21
x= -3
6/ Suy ra: 20 - 5x + 7x - 14 = -2
2x = -8
x = -4
7/ Suy ra: 4x +15 -5x = 7
-x = -8
x = 8
8/ Suy ra: 5x - 35 +30 -10x = 20
-5x - 5 = 20
-5x = 25
x = -5
9/ Suy ra: 35 - 7x + 5x - 10 = 15
-7x + 5x = 15 +10 - 35
-2x = -10
x = 5
Bài toán 3 : Tìm x, biết.
a. 2(x – 5) – 3(x + 7) = 14 b. 5(x – 6) – 2(x + 3) = 12
c. 3(x – 4) – (8 – x) = 12 d. -7(3x – 5) + 2(7x – 14) = 28
e. 5(3 – 2x) + 5(x – 4) = 6 – 4x f. -5(2 – x) + 4(x – 3) = 10x – 15
g. 2(4x – 8) – 7(3 + x) = |-4|(3 – 2) h. 8(x – |-7|) – 6(x – 2) = |-8|.6 – 50
k. -7(5 – x) – 2(x – 10) = 15 l. 4(x – 1) – 3(x – 2) = -|-5|
m. -4(x + 1) + 89x – 3) = 24 n. 5(x – 30 – 2(x + 6) = 9
o. -3(x – 5) + 6(x + 2) = 9 p. 7(x – 9) – 5(6 – x) = – 6 + 11x
q. 10(x – 7) – 8(x + 5) = 6.(-5) + 24
nhiều quá :((
\(a,2\left(x-5\right)-3\left(x+7\right)=14\)
\(2x-10-3x-21=14\)
\(-x-31=14\)
\(-x=45\)
\(x=45\)
\(b,5\left(x-6\right)-2\left(x+3\right)=12\)
\(5x-30-2x-6=12\)
\(3x-36==12\)
\(3x=48\)
\(x=16\)
\(c,3\left(x-4\right)-\left(8-x\right)=12\)
\(3x-12-8+x=0\)
\(4x-20=0\)
\(4x=20\)
\(x=5\)
Cố nốt nha bn !
cảm ơn, bn nha:)))
mà hình như bạn TOP 3 trả lời câu hỏi pải ko nhỉ???
d, \(-7\left(3x-5\right)+2\left(7x-14\right)=28\)
\(\Leftrightarrow-21x+35+14x-28=28\Leftrightarrow-7x=21\Leftrightarrow x=-3\)
e, \(5\left(3-2x\right)+5\left(x-4\right)=6-4x\)
\(\Leftrightarrow15-6x+5x-20=6-4x\Leftrightarrow-5-x=6-4x\)
\(\Leftrightarrow-11+3x=0\Leftrightarrow x=\frac{11}{3}\)
f, \(-5\left(2-x\right)+4\left(x-3\right)=10x-15\)
\(\Leftrightarrow-10+5x+4x-12=10x-15\Leftrightarrow-22+9x=10x-15\)
\(\Leftrightarrow-7-x=0\Leftrightarrow x=-7\)
a) (3/4 + x ) × 7/4 - 5 = 7/6
b) X × 12 + 13 × x + x ÷ 2 + 195 =1995
c) (x + 1 ) + (x + 4 ) + (x + 7) + ...... + ( x + 28 ) = 156
a) \(\left(\frac{3}{4}+x\right)\times\frac{7}{4}-5=\frac{7}{6}\)
\(\Leftrightarrow\left(\frac{3}{4}+x\right)\times\frac{7}{4}=\frac{37}{6}\)
\(\Leftrightarrow\frac{3}{4}+x=\frac{37}{6}:\frac{7}{4}=\frac{74}{21}\)
\(\Leftrightarrow x=\frac{74}{21}-\frac{3}{4}=\frac{233}{84}\)
Vậy ....
b) \(x\times12+13\times x+x:2+195=1995\)
\(\Leftrightarrow x\times12+x\times13+x\times0,5=1800\)
\(\Leftrightarrow x\times\left(12+13+0,5\right)=1800\)
\(\Leftrightarrow x\times25,5=1800\)
\(\Leftrightarrow x=\frac{1200}{17}\)
c) (x+1)+(x+4)+(x+7)+....+(x+28) = 156
<=> (x+x+x+...+x)+(1+4+7+...+28) = 156
<=> 10x + 145 = 156
<=> 10x = 11
<=> x = 1,1
Vậy ...
x-10/1994+X-8/1996+X-6/1998/+ X-4/2000+X-2/2002=X-2002/2+X-2000/4+X-1998/6+X-1996/8+X-1994/10
(X -10/1994 -1) + (X-8/1996 - 1) + (X-6/1998 - 1)+ (X-4/2000 - 1) + (X-2/2002 - 1) = (X-2002/2 - 1) + (X-2000/4 - 1) + (X-1998/6 - 1) + (X-1996/8 - 1) + (X-1994/10 - 1)
=> x-2004/1994 + x-2004/1996 + x-2004/1998 + x-2004/2000 + x-2004/2002 = x-2004/2 + x-2004/4 + x-2004/6 + x-2004/8 + x-2004/1994
=> x-2004/1994 + x-2004/1996 + x-2004/1998 + x-2004/2000 + x-2004/2002 - x-2004/2 - x-2004/4 - x-2004/6 - x-2004/8 - x-2004/1994 = 0
=> (x - 2004)(1/994 + 1/1996 + 1/1998 + 1/2000 + 1/2002 + 1/2 + 1/4 + 1/6 + 1/8) = 0
Mà (1/994 + 1/1996 + 1/1998 + 1/2000 + 1/2002 + 1/2 + 1/4 + 1/6 + 1/8) \(\ne\)0
=> x - 2004 = 0
=> x = 2004
Vậy x = 2004
Sửa (x - 2004) (1/1994 + 1/1996 + 1/1998/+ 1/2000 + 1/2002 + 1/2 + 1/4 + 1/6+ 1/8 + 1/10)
= (x - 2004) (1/1994 + 1/1996 + 1/1998/+ 1/2000 + 1/2002 - 1/2 -1/4 - 1/6 - 1/8 - 1/10)
:)))
1)-7.(5-x)-2.(x-10)=15
2)3.(x-4)-(8-x)=12
3)7.(x-9)-5.(6-x)=(-6)+11x
làm đi cho tick PLEASE!!!!!!!!!!
1.
$-7(5-x)-2(x-10)=15$
$-35+7x-2x+20=15$
$5x-15=15$
$5x=30$
$x=30:5=6$
2.
$3(x-4)-(8-x)=12$
$3x-12-8+x=12$
$4x-20=12$
$4x=12+20=32$
$x=32:4=8$
3.
$7(x-9)-5(6-x)=(-6)+11x$
$7x-63-30+5x=11x-6$
$12x-93=11x-6$
$12x-11x=93-6$
$x=87$
a,x-10/1994+x-8/1996+x-6/1998+x-4/2000+x-2/2002=x-2002/2+x-2000/4+x-1998/6+x-1996/8+x-1994/10
b,x-1991/9+x-1993/7+x-1995/5+x-1997/3+x-1999/1=x-9/1991+x-7/1993+x-5/1995+x-3/1997+x-1/1999
c,x-1/13-2x-13/15=3x-15/27-4x-27/29
x-10/1994+x-8/1996+x-6/1998+x-4/2000+x-9/2002=x-2002/2+x-2000/4
+x-1998/6+x-1996/8+x-1994/10
x-10/1994+x-8/1996+x-6/1998+x-4/2000+x-9/2002=x-2002/2+x-2000/4
+x-1998/6+x-1996/8+x-1994/10
a,(x+2)+(x+4)+(x+6)+...+(x+100)=2650
b,(x+9)+(x-2)+(x+7)+(x-4)+(x+5)+(x-6)+(x+3)+(x-8)+(x+1)=95
c,(x*1+1)+(x*2+4)+(x*3+7)+(x*4+10)+...+(x*n+28)=200