tìm x
( x +2 ) + ( x + 5 ) + ( x + 9 ) + ( x + 11 ) = 5 . x
Trong bài toán tìm x của lơp 6 có được dùng dấu suy ra như thế này không?
ví dụ: Tìm x, biết 2(x+5) - 7 = 11
=> 2(x+5) = 18
=> x+5 = 9
=> x = 4
hay phải giải như ở cấp tiểu học
2(x+5) - 7 = 11
2(x+5) = 11+7=18
x+5 = 18:2=9
x = 9 - 5=4
sang cấp 2 có thể sử dụng dấu suy ra nha bn
bài 1 : tìm x
a, 1/5=5=1/2 b, 11/5+x=9
c,5-x=7/17 d, x-1/3=16/5:3/2
e,8/9:x=11/2 g, x:31/5=2+7/2
h,7/8x íc=29/2-2
giải hết ra cho mink nha
BÀI 3 : Tìm số nguyên x, biết
a, 5/8= x14 x/6= 1/-3 3/-5= x/10 3/5= -9/11
x/2= 2/x x/-5= -5/x
\(a,\dfrac{5}{8}=\dfrac{x}{14}\)
\(\Rightarrow x=\dfrac{5.14}{8}=8,75\)
Vậy \(x=8,75\)
\(b,\dfrac{x}{6}=-\dfrac{1}{3}\)
\(\Rightarrow x=-\dfrac{1.6}{3}=-2\)
Vậy \(x=-2\)
\(c,-\dfrac{3}{5}=\dfrac{x}{10}\)
\(\Rightarrow x=-\dfrac{3.10}{5}=-6\)
Vậy \(x=-6\)
câu d đã có đáp án
\(+\text{)}\dfrac{5}{8}=14x\)⇒\(x=\dfrac{5}{112}\)
\(+\text{)}\dfrac{x}{6}=-\dfrac{1}{3}\)⇒\(x=-2\)
\(+\text{)}-\dfrac{3}{5}=\dfrac{x}{10}\)⇒\(x=-6\)
\(+\text{)}\dfrac{3}{5}=-\dfrac{9}{11}\)⇒\(\dfrac{33}{55}=\dfrac{45}{55}\)
\(+\text{)}\dfrac{x}{2}=\dfrac{2}{x}\)⇒\(x=+-2\)
\(+\text{)}\dfrac{x}{-5}=\dfrac{-5}{x}\)⇒\(x=+-5\)
Tìm x ∈ Z, biết:
a) x + 5 = -2 + 11
b) -3x = -5 + 29
c) | x | - 9 = -2 + 17
d) | x – 9 | = -2 + 17
a) x = 4
b) x = -8
c) | x | - 9 = -2 + 17
| x | = 15 + 9
| x | = 24
x = 24 hoặc x = -24
d) |x – 9| = -2 + 17
|x – 9| = 15
x – 9 = 15 hoặc x – 9 = -15
x = 24 hoặc x = -6
tìm x biết
1) x=-1/2 + 3/4 2) x - 1/5 = 2/11 3) x - 5/6 = 16/42 + -8/56
4) x/5 = 5/6 + -19/30 5) |x| - 1/4 = 6/18 6)x = -1/2 +3/4
7) x/15 = 3/5 + -2/3 8)11/8 + 13/6 = 85/x 9) x - 7/8 = 13/12
10) x - -6/15 = 4/27 11) -\(\dfrac{-6}{12}\)+ x = 9/48 12) x - 4/6 = 5/25 + -7/15
1: x=3/4-1/2=3/4-2/4=1/4
2: x-1/5=2/11
=>x=2/11+1/5=21/55
3: x-5/6=16/42-8/56
=>x-5/6=8/21-4/28=5/21
=>x=5/21+5/6=15/14
4: x/5=5/6-19/30
=>x/5=25/30-19/30=6/30=1/5
=>x=1
5: =>|x|=1/3+1/4=7/12
=>x=7/12 hoặc x=-7/12
6: x=-1/2+3/4
=>x=3/4-1/2=1/4
11: x-(-6/12)=9/48
=>x+1/2=3/16
=>x=3/16-1/2=-5/16
1)x= 1/4
2)x= 2/11+ 1/5
x= 21/55
3)x - 5/6 = 5/21
x = 5/21+5/6
x = 15/14
4)x/5 = 5/6 + -19/30
x:5 = 1/5
x = 1/5.5
x = 1
5) |x| - 1/4 = 6/18
|x| = 6/18 - 1/4
|x| =7/12
⇒x= 7/12 hoặc -7/12
6)x = -1/2 +3/4
x= 1/4
7) x/15 = 3/5 + -2/3
x:15 = -1/15
x = -1/15. 15
x = -1
8)11/8 + 13/6 = 85/x
85/24 = 85/x
⇒ x = 24
9) x - 7/8 = 13/12
x = 13/12 + 7/8
x = 47/24
10)x - -6/15 = 4/27
x = 4/27 + (-6/15)
x = -34/135
11) -(-6/12)+x = 9/48
x= 9/48 - 6/12
x = -5/16
12) x - 4/6 = 5/25 + -7/15
x -4/6 = -4/15
x = -4/15 + 4/6
x = 2/5
Tìm X
a) 4/7 x X - 1/5 = 5/9 b)9/15 + 11/15 : X = 2/3
a) \(\dfrac{4}{7}\times x=\dfrac{5}{9}+\dfrac{1}{5}=\dfrac{34}{45}\)
\(x=\dfrac{34}{45}:\dfrac{4}{7}=\dfrac{119}{90}\)
b) \(\dfrac{11}{15}:x=\dfrac{2}{3}-\dfrac{9}{15}=\dfrac{1}{15}\)
\(x=\dfrac{11}{15}:\dfrac{1}{15}=11\)
a) 4/7 x X - 1/5 = 5/9
4/7 x X = 5/9 + 1/5
4/7 x X = 34/45
X = 34/45 : 4/7
X = 119/90
b)9/15 + 11/15 : X = 2/3
11/15 : X = 2/3 - 9/15
11/15 : X = 1/15
X = 11/15 : 1/5
X = 11
Tìm x ∈ Z, biết:
a) x + 9 = 2 - 17
b) x - 17 = (-11) . (-5)
c) |x – 5| = - 4 2
a) x + 9 = 2 - 17
x + 9 = - 15
x = -15 – 9
x = -24
Vậy x = -24
b) x - 17 = (-11) . (-5)
x – 17 = 55
x = 17 + 55
x = 72
c)| x – 5 | = (-4)2
| x – 5 | = 16
x – 5 = 16 hoặc x – 5 = -16
x = 21 hoặc x = -11
1. Tìm X, biết: x - \(\dfrac{2}{3}\) x ( X + 9 ) = 1
2. Tìm X, biết: X - \(\dfrac{11}{15}\) = \(\dfrac{3+X}{5}\)
\(1.x-\dfrac{2}{3}\times\left(x+9\right)=1\)
\(x-\dfrac{2}{3}\times x-6=1\)
\(x\times\left(1-\dfrac{2}{3}\right)=7\)
\(x\times\dfrac{1}{3}=7\)
\(x=21\)
\(2.x-\dfrac{11}{15}=\dfrac{3+x}{5}\)
\(\dfrac{15x}{15}-\dfrac{11}{15}=\dfrac{9+3x}{15}\)
\(15x-11=9+3x\)
\(12x=20\)
\(x=\dfrac{5}{3}\)
Tìm giá trị của 11 x 10 - 10 x 9 + 9 x 8 - 8 x 7 + 7 x 6 - 6 x 5 + 5 x 4 - 4 x 3 + 3 x 2 - 2 x 1.
11 x 10 - 10 x 9 + 9 x 8 - 8 x 7 + 7 x 6 - 6 x 5 + 5 x 4 - 4 x 3 + 3 x 2 - 2 x 1 = 60