(y+1)+(y+4)+(y+7)+......+(y+26)=156. Tìm y
(1+y)+(4+y)+(7+y)+.........(28+y)=156
Ta có : (1 + y) + (4 + y) + (7 + y) + ...... + (28 + y) = 156
=> (y + y + ..... + y) + (1 + 4 + 7 + ..... + 28) = 156
=> 10y + 145 = 156
=> 10y = 11
=> y = 11/10
\(\left(1+y\right)+\left(4+y\right)+\left(7+y\right)+...+\left(28+y\right)=156\)
\(\left(1+4+7+...+28\right)+\left(y+y+y+y+...+y\right)=156\)
\(145+10y=156\)
\(10y=156-145\)
\(10y=11\)
\(y=11\div10\)
\(y=1,1\)
\(\left(1+y\right)+\left(4+y\right)+\left(7+y\right)+....+\left(28+y\right)=156\)
\(\left(1+4+7+...+28\right)+10x=156\)
\(145+10x=156\)
\(10x=156-145\)
\(10x=11\)
\(\Rightarrow x=1,1\)
Bài 1 Tìm x, y
a, x=3y và y-x=26
b,x/5 = y/7 và 2x+y=26
\(x=3y\); \(y-x=26\)
từ \(y-x=26\Rightarrow x=y-26\)
thay \(x=y-26\), ta được:
\(y-26=3y\)
\(\Rightarrow2y=-26\)
\(\Rightarrow y=-13\)mà \(x=3y\Rightarrow x=3\cdot\left(-13\right)=-39\)
vậy \(x=-39;y=-13\)
Ta có : \(\frac{x}{5}=\frac{y}{7}\Rightarrow5y=7x\Rightarrow x=\frac{5y}{7}\)
Thay \(x=\frac{5y}{7}\)vào biểu thức \(2x+y=26\);ta được:
\(\frac{2.5y}{7}+y=26\Rightarrow10y+7y=26.7\Rightarrow17y=182\Rightarrow y=\frac{182}{17}\)
Do đó : \(x=\frac{\frac{5.182}{17}}{7}=\frac{130}{17}\)
Tìm y:
y X\(\frac{52}{26}=\frac{17}{13}\)
\(4\frac{1}{2}:y=\frac{2}{7}\)
\(y.\frac{52}{26}=\frac{17}{13}\)
\(y=\frac{17}{13}:\frac{52}{26}\)
\(y=\frac{17}{26}\)
\(4\frac{1}{2}:y=\frac{2}{7}\)
\(\frac{9}{2}:y=\frac{2}{7}\)
\(y=\frac{9}{2}:\frac{2}{7}\)
\(y=\frac{63}{4}\)
\(y\times\frac{52}{26}=\frac{17}{13}\)
\(y=\frac{17}{13}:\frac{52}{26}\)
\(y=\frac{221}{338}\)
\(4\frac{1}{2}:y=\frac{2}{7}\)
\(y=4\frac{1}{2}:\frac{2}{7}\)
\(y=\frac{63}{4}\)
y + y x y x 1/3 : 2/9 + y : 2/7 = 252
(4/5 : 6/5 + 1/5 : 1/y) x 30 - 26 += 54
Tìm n để A chia hết cho B:
a, A= -13x^17 y^2n-3+22x^16 y^7 và B= -7x^3n+1 y^26
b, A= 20x^8y 2n-10x^4 y^3n+15x^5 y^6 và B= 3x^2n y^n+1
Giúp mk với mn oi. Mk cảm ơn😫😥
tìm y
y x 4 7/12=6 1/4
y : 3 7/8=5 1/2
6 1/7 : y =5 2/5
\(y.3\dfrac{7}{12}=6\dfrac{1}{4}\)
\(y.\dfrac{43}{12}=\dfrac{25}{4}\)
\(y=\dfrac{25}{4}:\dfrac{43}{12}\)
\(y=\dfrac{25.12}{4.43}\)
\(y=\dfrac{75}{43}\)
Tìm y biết :
y x ( 26 + 327 ) = 327 x 7 + 26 x 7
y x ( 26 + 327 ) = 327 x 7 + 26 x 7
y x 353 = 2471
y = 2471 : 353
y = 7
y x (25 + 327) = 327 x 7 + 26 x 7
y x 352 = (327 + 26) x 7
y x 352 = 353 x 7
y x 352 = 2471
y = 2471 : 352
y = 2471/352
đúng thì ủng hộ vs
sorry tính lộn
y x (26 + 327) = 327 x 7 + 26 x 7
y x 353 = 2471
y = 2471 : 353
y = 7
bài kia lộn nha
[y+4]+[y+6]+[y+8]+...+[y+26] bằng 210 tìm y
Bài làm:
Ta có: \(\left(y+4\right)+\left(y+6\right)+\left(y+8\right)+...+\left(y+26\right)=210\)
\(\Leftrightarrow\left(y+y+...+y\right)+\left(4+6+...+26\right)=210\)
\(\Leftrightarrow12y+\frac{\left(26+4\right).12}{2}=210\)
\(\Leftrightarrow12y+180=210\)
\(\Leftrightarrow12y=30\)
\(\Rightarrow y=\frac{5}{2}\)
(y + 4) + (y + 6) + (y + 8) +...+ (y + 26) = 210
y + 4 + y + 6 + y + 8 +...+ y + 26 = 210
y + y + y +..+ y + 4 + 6 + 8 +...+ 26 = 210
Từ 4 đến 26 với quy luật như trên có số số hạng là:
(26 - 4) ÷ 2 + 1 = 12 (số hạng)
12.y + \(\frac{\left(4+26\right)\times12}{2}\)= 210
12.y + 180 = 210
12.y = 210 - 180
12.y = 30
y = 30 ÷ 12
y = 2,5
Trả lời:
\(\left(y+4\right)+\left(y+6\right)+\left(y+8\right)+...+\left(y+26\right)=210\)
\(\Leftrightarrow\left(y+y+y+...+y\right)+\left(4+6+8+...+26\right)=210\)
\(\Leftrightarrow12x+\left(26+4\right)\times\left[\left(26-4\right)\div2+1\right]\div2=210\)
\(\Leftrightarrow12y+30\times12\div2=210\)
\(\Leftrightarrow12y+180=210\)
\(\Leftrightarrow12y=30\)
\(\Leftrightarrow y=\frac{5}{2}\)
Tìm y biết :
( y + 4 ) + ( y + 6 ) + ( y + 8 ) + ... + ( y + 26 ) = 210
= y + 4 + y + 6 + y + 8 + ... + y + 26 = 210
=> (y + y + y+ ... + y) + (4 + 6 + 8 + ... + 26) = 210
=> 12y + 180 = 210
12y = 210 -180
12y = 30
y = 30 : 12
y = 2.5
Đáp số : 2.5
( y + 4 ) + ( y + 6 ) + ( y + 8 ) + ..... + ( y + 26 ) = 210
y + ( 4 + 6 + 8 + .... + 26 = 210
y + 44 = 210
y = 210 - 44
y = 160