Tìm x:
x - 5 + 1 + ( 46 - 12 ) = 90
Tìm x biết:
2 x X +68 = 126
3 x X -24 = 90
84 - 4 x X =16
(5 x X + 10 ) + 35 = 70
(6 x X - 18) - 42 =12
( 2 x X - 4 ) + 24
45 - ( 3 x X - 9 ) = 15
60 + (10 x X - 40 ) = 90
145 - (5 x X + 15 ) = 65
84 - ( 2 x X - 8 ) = 46
2 x X + 68 = 126
2 x X = 126 - 68
2 x X = 58
x = 58 : 2
x = 29
a) \(2\times x+68=126\)
\(\Rightarrow2\times x=58\)
\(\Rightarrow x=29\)
b) \(3\times x-24=90\)
\(\Rightarrow3\times x=123\)
\(\Rightarrow x=41\)
c) \(84-4\times x=16\)
\(\Rightarrow4\times x=84-16=68\)
\(\Rightarrow x=17\)
d) \(\left(5\times x+10\right)+35=70\)
\(\left(5\times x+10\right)=70-35\)
\(\Rightarrow5\times x+10=35\)
\(\Rightarrow5\times x=25\)
\(\Leftrightarrow x=5\)
e) Tương tự d
f) Thiếu kết quả của đề
g) \(45-\left(3\times x-9\right)=15\)
\(\Rightarrow(3\times x-9)=45-15\)
\(\Rightarrow3\times x-9=30\)
\(\Rightarrow3\times x=39\)
\(\Rightarrow x=13\)
-- Các câu còn lại tương tự câu g
Tìm số nguyên x, y biết:
a, \(\dfrac{-1}{5}\)≤ \(\dfrac{x}{8}\)≤ \(\dfrac{1}{4}\)
b, \(\dfrac{4}{x-6}\)= \(\dfrac{y}{24}\)= \(\dfrac{-12}{18}\)
c, \(\dfrac{x+46}{20}\)=x \(\dfrac{2}{5}\)
Giải:
a) \(\dfrac{-1}{5}\le\dfrac{x}{8}\le\dfrac{1}{4}\)
\(\Rightarrow\dfrac{-8}{40}\le\dfrac{5x}{40}\le\dfrac{10}{40}\)
\(\Rightarrow5x\in\left\{0;\pm5;10\right\}\)
\(\Rightarrow x\in\left\{0;\pm1;2\right\}\)
b) \(\dfrac{4}{x-6}=\dfrac{y}{24}=\dfrac{-12}{18}\)
\(\Rightarrow\dfrac{4}{x-6}=\dfrac{-12}{18}\)
\(\Rightarrow-12.\left(x-6\right)=4.18\)
\(\Rightarrow-12x+72=72\)
\(\Rightarrow-12x=72-72\)
\(\Rightarrow-12x=0\)
\(\Rightarrow x=0:-12\)
\(\Rightarrow x=0\)
\(\Rightarrow\dfrac{y}{24}=\dfrac{-12}{18}\)
\(\Rightarrow y=\dfrac{-12.24}{18}=-16\)
c) \(\dfrac{x+46}{20}=x.\dfrac{2}{5}\)
\(\dfrac{x+46}{20}=\dfrac{2x}{5}\)
\(\Rightarrow5.\left(x+46\right)=2x.20\)
\(\Rightarrow5x+230=40x\)
\(\Rightarrow5x-40x=-230\)
\(\Rightarrow-35x=-230\)
\(\Rightarrow x=-230:-35\)
\(\Rightarrow x=\dfrac{46}{7}\)
Chúc bạn học tốt!
Tìm x, biết 12 chia hết cho x và a < -2
A. x ∈ − 1 .
B. x ∈ − 3 ; − 4 ; − 6 ; − 12 .
C. x ∈ − 2 ; − 1 .
D. x ∈ − 2 ; − 1 ; 1 ; 2 ; 3 ; 46 ; 12 .
Đáp án là B vì 12: -3 = -4; 12: -4 = -3; 12: -6 = -2;12: -12 = -1 và đáp ứng điều kiện a< -2
Tìm các số nguyên x;y biết
a) -5/8=x/16 ; 3x/9=2/6
b) x+3/15=1/3 ; 6/2x+1=2/7
c)4/x-6=y/24=-12/18 ; 3-x/-12=16/y+1=192/-72
d)-2/3<x/5<-1/6 ; -1/5<(hoặc =)x/8<(hoặc =)1/4
e)x+46/20=x 2/5 ; y 5/y=86/y
(Lưu ý: x 2/5;y 5/y là các số hỗn)
Giúp mình với,cảm ơn nhìu :33 moazz!
Giải:
a) \(\dfrac{-5}{8}=\dfrac{x}{16}\)
\(\Rightarrow x=\dfrac{16.-5}{8}=-10\)
\(\dfrac{3x}{9}=\dfrac{2}{6}\)
\(\Rightarrow3x=\dfrac{2.9}{6}=3\)
\(\Rightarrow x=1\)
b) \(\dfrac{x+3}{15}=\dfrac{1}{3}\)
\(\Rightarrow x+3=\dfrac{1.15}{3}=5\)
\(\Rightarrow x=2\)
\(\dfrac{6}{2x+1}=\dfrac{2}{7}\)
\(\Rightarrow2x+1=\dfrac{6.7}{2}=21\)
\(\Rightarrow x=10\)
c) \(\dfrac{4}{x-6}=\dfrac{y}{24}=\dfrac{-12}{18}\)
\(\Rightarrow\dfrac{4}{x-6}=\dfrac{-12}{18}\)
\(\Rightarrow x-6=\dfrac{18.4}{-12}=-6\)
\(\Rightarrow x=0\)
\(\Rightarrow\dfrac{y}{24}=\dfrac{-12}{18}\)
\(\Rightarrow y=\dfrac{-12.24}{18}=-16\)
\(\dfrac{3-x}{-12}=\dfrac{16}{y+1}=\dfrac{192}{-72}\)
\(\Rightarrow\dfrac{3-x}{-12}=\dfrac{192}{-72}\)
\(\Rightarrow3-x=\dfrac{192.-12}{-72}=32\)
\(\Rightarrow x=-29\)
\(\Rightarrow\dfrac{16}{y+1}=\dfrac{192}{-72}\)
\(\Rightarrow y+1=\dfrac{16.-72}{192}=-6\)
d) \(\dfrac{-2}{3}< \dfrac{x}{5}< \dfrac{-1}{6}\)
\(\Rightarrow\dfrac{-20}{30}< \dfrac{6x}{30}< \dfrac{-5}{30}\)
\(\Rightarrow6x\in\left\{-18;-12;-6\right\}\)
\(\Rightarrow x\in\left\{-3;-2;-1\right\}\)
\(\dfrac{-1}{5}\le\dfrac{x}{8}\le\dfrac{1}{4}\)
\(\Rightarrow\dfrac{-8}{40}\le\dfrac{5x}{40}\le\dfrac{10}{40}\)
\(\Rightarrow5x\in\left\{-5;0;5;10\right\}\)
\(\Rightarrow x\in\left\{-1;0;1;2\right\}\)
e) \(\dfrac{x+46}{20}=x\dfrac{2}{5}\)
\(\Rightarrow\dfrac{x+46}{20}=x+\dfrac{2}{5}\)
\(\Rightarrow\dfrac{x+46}{20}=\dfrac{5x+2}{5}\)
\(\Rightarrow5.\left(x+46\right)=20.\left(5x+2\right)\)
\(\Rightarrow5x+230=100x+40\)
\(\Rightarrow5x-100x=40-230\)
\(\Rightarrow-95x=-190\)
\(\Rightarrow x=-190:-95\)
\(\Rightarrow x=2\)
\(y\dfrac{5}{y}=\dfrac{86}{y}\)
\(\Rightarrow y+\dfrac{5}{y}=\dfrac{86}{y}\)
\(\Rightarrow\dfrac{y^2+5}{y}=\dfrac{86}{y}\)
\(\Rightarrow y^2+5=86\)
\(\Rightarrow y^2=86-5\)
\(\Rightarrow y^2=81\)
\(\Rightarrow\left[{}\begin{matrix}y=9\\y=-9\end{matrix}\right.\)
Chúc bạn học tốt!
gọi 2.xOy = (5.x+12) độ và aOb = (3.x + 46) độ là 2 góc đối đỉnh. tìm x
Tìm x
1/3—1/12—1/30—1/42—1/56—1/72—1/90 —1/110=x—5/13
Các bạn giải những bài toán tìm x;y giùm mình nha
a)X - 15 =90 - 35
b)X*23 =46 - 0
c)X +46 = 10
a)X - 15 =90 - 35
x-15=55
x=55+15
x=70
b)X*23 =46 - 0
x*23=46
x=46:23
x=2
c)X +46 = 10
x=10-46
x=-36
a, X= 90 - 35 +15 = 40
B,X=46/23=2
C, X=10-46= - 36
1.Tính:
34 x 2 =
46 x 6 =
56 x 5 =
11 x 5 =
47 x 5 =
45 x 5 =
77 x 6 =
90 x 5 =
99 x 5 =
12 x 6 =
11 x 4 =
23 x 4 =
45 x 6 =
2. Tìm x:
34 x X = 102
3. Tính :
45 : 6 = ....(dư...)
34 : 5 = ....(dư...)
45 : 5 =
54 : 6 =
4. Sắp xếp các số 1,2,3,4,5,6,7,8,9,0 thành số chẫn có hai số và bao nhiêu số có hai chữ số chẫn ?
1) Tính:
34 x 2= 68; 46 x 6=276; 56 x 5= 280; 11 x 5= 55; 47 x 5= 235; 45 x 5= 225; 77 x 6= 462; 90 x 5= 450; 12 x 6= 72; 11x4=44; 23x4=92; 45 x 6= 270.
2) Tìm x:
34 x X = 102
=> X = 102 - 34
=> X = 68
3) Tính;
45 : 6 = 7 ( dư 3)
34 : 5 = 6 ( dư 4)
45 : 5 = 9
54 : 6 = 9
4) .....
a) các số là: 12,14,16,18,10;22,24,26,28,20;32,34,36,68,30;42,44,46,48,49,40;52,54,56,58,50;62,64,66,68,60;72,74,76,78,70;82,84,86,88,80;92,94,96,98,90.
b) có tất cả 40 số.
bài 1
34x2=68
46x6=276
56x5=280
11x5=55
47x5=235
45x5=225
77x6=462
90x5=450
99x5=495
12x6=72
11x4=44
23x4=92
45x6=270
Bài 2
34 x X = 102
X = 102 : 34
X = 3
Bài 3
45:6=7(dư 3)
34:5=6(dư 4)
45:5=9
54:6=9
Bài 4
45
k nha,bài 4 mình ko chắc lắm
34 x 2 = 68 46 x 6 = 276 56 x 5 =280 11 x 5 = 55 47 x 5 = 235 45 x 5 = 225 77 x 6 = 462 90 x 5 = 450 99 x 5 =495 12 x 6 = 72 11 x 4 = 44 23 x 4 = 92 45 x 6 = 270
Bai 2: Tim X 34 x X= 102 x= 102:34 x= 3
Tìm x
a, x : 46/15 = 13/12
b, -2/3x + 1/5 = 3/10
c, x : 13/3 = -2,5
d, 2/4x + 2/5x = 1
a, x : 46 / 15 = 13 / 12
x = 13/12 . 46/15
x = 299/90
b, - 2/3x + 1 / 5 = 3 / 10
- 2 / 3 x = 3 / 10 - 1 / 5
- 2 / 3 x = 1 / 10
x = -3 / 20
c, x : 13 / 3 = - 2 / 5
x = - 2 / 5 . 13 / 3
x = -26 /15
d, 2 / 4 x + 2 / 5 x = 1
x ( 2 / 4 + 2 / 5 ) = 1
x . 9 / 10 = 1
x = 10 / 9