Tìm x ,biết
5.(x+17)—16=—1
Tìm x ∈ ℕ , biết:
a ) 1 2 + − 1 3 + − 2 3 ≤ x < − 3 5 + 1 6 + − 2 5 + 3 2 b ) − 3 8 + − 18 21 + − 1 7 < x ≤ − 1 6 + 8 17 + 5 − 6 + 9 17 + 1
a ) − 1 2 ≤ x < 2 3 = > x = 0. b ) − 1 < x ≤ 1 = > x ∈ {0;1}
Tìm số nguyên x, biết:
1) -16 + 23 + x = - 16
2) 2x – 35 = 15
3) 3x + 17 = 12
4) (2x – 5) + 17 = 6
5) 10 – 2(4 – 3x) = -4
6) - 12 + 3(-x + 7) = -18
Tìm số nguyên x, biết:
1) -16 + 23 + x = - 16
7+x=-16
x=-16-7
x=-23
2) 2x – 35 = 15
2x=15+35
2x=50
x=50:2
x=25
3) 3x + 17 = 12
3x=12-17
3x=-5
x=-5/3
4) (2x – 5) + 17 = 6
2x-5=6-17
2x-5=-11
2x=-11+5
2x=-6
x=-6:2
x=-3
5) 10 – 2(4 – 3x) = -4
2(4-3x)=10-(-4)
2(4-3x)=14
4-3x=14:2
4-3x=7
3x=4-7
3x=-3
x=-3:3
x=-1
6) - 12 + 3(-x + 7) = -18
3(-x+7)=-18-(-12)
3(x+7)=-6
x+7=-6:3
x+7=-2
x=-2-7
x=-9
tự đi mà làm
Tìm x, biết :
3/2 + 5/4 + 9/8 + 17/16 + 33/32 - 6 + x-1/x+1 = 31/32 - 2/2015
3/2+5/4+9/8/+17/16+33/32-6+x-1/x+1=31/32-2/2015
=(1+1/2)+(1+1/4)+(1+1/8)+(1+1/16)+(1+1/32-6+x-1/x+1=31/32-2/2015
=(1/2+1/4+1/8+1/16+1/32)+(1+1+1+1+1)-6+x-1/x+1=31/32-2/2015
=31/32+5-6+x-1/x+1=31/32-2/2015
=5-6+x-1/x+1=31/32-2/2015-31/32
=-1+x-1/x+1=-2/2015
=x-1/x+1=-2/2015- -1
=x-1/x+1=2013/2015
=>x=2014
tìm sood nguyên x biết
5 - x = 17 - (-5)
9-25 = (-7 - x ) - ( 25 - 7)
17 - { -x - [-x - (-x) ] } = -16
\(5-x=17-\left(-5\right)\)
\(5-x=22\)
\(x=5-22\)
\(x=-17\)
a/ 5 - x = 17 - (-5)
5-x = 22
x= -17
b/ 9-25 = (-7 - x ) - ( 25 - 7)
ko biết làm
c cx v luôn
Bài 5 ( 1 điểm) Tìm y, biết:
a. 16 307 : y = 45 ( dư 17) b. y x 52 + y x 48 = 36 700
\(a.16307:y=45\left(dư\text{ }17\right)\)\(\Leftrightarrow45\text{×}y+17=16307\)
\(45\text{×}y=16307-17\)
\(45\text{×}y=16290\)
\(y=16290:45\)
\(y=362\)
\(b.y\text{×}52+y\text{×}48=36700\)
\(y\text{×}\left(52+48\right)=36700\)
\(y\text{×}100=36700\)
\(y=36700:100\)
\(y=367\)
a) 16307= 45*y+17 -> y=(16307-17)/45= 362
b) y*(52+48)= 36700 -> y=36700/100= 367
Tìm số nguyên x, biết:
a) x – 32 = − 5 − 17
b) 16 – x = 21 – − 8
c) 106 − x = − 58 – 8
a) x – 32 = − 5 − 17 ⇔ x – 32 = − 32 ⇔ x = − 32 + 32 ⇔ x = 0.
b) 16 – x = 21 – − 8 ⇔ 16 – x = 21 + 8 ⇔ 16 − x = 30 ⇔ − x = 30 − 16 ⇔ − x = 14 ⇔ x = − 14.
c) 106 − x = − 58 – 8 ⇔ 106 − x = − 66 ⇔ − x = − 66 − 106 ⇔ − x = − 172 ⇔ x = 172.
Tìm x, biết:
\(1\frac{3}{5}+\left(\frac{\frac{2}{7}+\frac{2}{17}+\frac{2}{37}}{\frac{5}{7}+\frac{5}{17}+\frac{5}{37}}\right).x=\frac{16}{5}\)
\(1\frac{3}{5}+\left(\frac{\frac{2}{7}+\frac{2}{17}+\frac{2}{37}}{\frac{5}{7}+\frac{5}{17}+\frac{5}{37}}\right)x=\frac{16}{5}\)
\(\Rightarrow\frac{2\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}{5\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}.x=\frac{16}{5}-\frac{8}{5}\)
\(\Rightarrow\frac{2}{5}.x=\frac{8}{5}\)
\(\Rightarrow x=\frac{8}{5}:\frac{2}{5}=4\)
vậy x=4
Tìm x biết : \(1\frac{2}{5}+\left(\frac{\frac{2}{7}+\frac{2}{17}+\frac{2}{37}}{\frac{5}{7}+\frac{5}{17}+\frac{5}{37}}\right)\times x=\frac{16}{5}\)
\(\frac{7}{5}+\left(\frac{2\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}{5\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}\right)\cdot x=\frac{16}{5}\)
\(\frac{2}{5}x=\frac{16}{5}-\frac{7}{5}\)
\(\frac{2}{5}x=\frac{9}{5}\)
x = \(\frac{9}{5}:\frac{2}{5}\)
x = 9/2
\(1\frac{2}{5}+\left(\frac{\frac{2}{7}+\frac{2}{17}+\frac{2}{37}}{\frac{5}{7}+\frac{5}{17}+\frac{5}{37}}\right).x=\frac{16}{5}\)
\(\frac{7}{5}+\left[\frac{2.\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}{5.\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}\right].x=\frac{16}{5}\)
\(\frac{7}{5}+\frac{2}{5}.x=\frac{16}{5}\)
\(\frac{2}{5}.x=\frac{16}{5}-\frac{7}{5}\)
\(\frac{2}{5}.x=\frac{9}{5}\)
\(x=\frac{9}{5}:\frac{2}{5}\)
\(x=\frac{9}{5}.\frac{5}{2}\)
\(x=\frac{9}{2}\)
\(\frac{7}{5}+\left(\frac{2\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}{5\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}\right).x=\frac{16}{5}\)
\(\frac{2}{5}x=\frac{16}{5}-\frac{7}{5}\)
\(\frac{2}{5}x=\frac{9}{5}\)
\(x=\frac{9}{5}\div\frac{2}{5}\)
\(x=\frac{9}{2}\)
Câu 1: Tìm x,y,z biết 2x/3=3y/4=4z/5 và x-2y+3z=-31
Câu 2: Tìm x biết x-6/7+x-7/8+x-8/9=x-9/10+x-10/11+x-11/12
Câu 3: A =1/15+1/16+1/17+...+1/44
CMR: A>5/6