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Số số hạng là:
( 215 - 32 ) : 1 + 1 = 184
Tổng là:
( 215 + 32 ) x 184 : 2 = 22724
Đáp số : 22724
Chúc bạn học tốt!
32+33+34+35+...+213+214+215
=(215+32)x[(215-32):1+1]:2
=247x184:2
=22724
Chúc bạn học giỏi nha!!!
![](https://rs.olm.vn/images/avt/0.png?1311)
Có : 5^214 + 5^213 - 5^212
= 5^212.(5^2+5-1)
= 5^212 . 29 chia hết cho 29
Tk mk nha
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) - (4x - 25) + (214 + 2x) = - x + 213
<=> - 4x + 25 + 214 + 2x = - x + 213
<=> - 2x + 239 = -x + 213
<=> - x = - 2x + 26
<=> 2x - 26 = x
<=> x = 26
b) (x + 2).(x - 7) = 0
<=> x + 2 = 0
hoặc x - 7 = 0
<=> x = - 2
hoặc x = 7
c) x3 - 2x2 = 0
<=> x3 = 2x2
<=> x2.x = 2x2
<=> x = 2
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(1-2+3-4+...+213-214\)
\(=\left(1-2\right)+\left(3-4\right)+...+\left(213-214\right)\)(có 107 cặp)
\(=\left(-1\right)+\left(-1\right)+...+\left(-1\right)\)
\(=-107\)
b) \(\left|x-17\right|+13=25\)
\(\Rightarrow\left|x-17\right|=25-13\)
\(\Rightarrow\left|x-17\right|=12\)
\(\Rightarrow\left[{}\begin{matrix}x-17=12\\17-x=12\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=12+17\\-x=12-17\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=29\\-x=-5\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=29\\x=5\end{matrix}\right.\)
Vậy \(\left[{}\begin{matrix}x=29\\x=5\end{matrix}\right.\)
\(1-2+3-4+5-6+...+213-214\)
\(=\left(1-2\right)+\left(3-4\right)+\left(5-6\right)+...+\left(213-214\right)\)
\(=\left(-1\right)+\left(-1\right)+\left(-1\right)+...+\left(-1\right)\)
\(=\left(-1\right)\left[\left(\dfrac{214-1}{1}+1\right):2\right]\)
\(=-1.107\)
\(=-107\)
\(\left|x-17\right|+13=25\)
\(\Rightarrow\left|x-17\right|=12\)
\(\Rightarrow\left[{}\begin{matrix}x-17=12\\x-17=-12\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=29\\x=5\end{matrix}\right.\)
![](https://rs.olm.vn/images/avt/0.png?1311)
A = 51 − 314 + 213 ; A = 51 − 314 − 213 B = 51 + 213 − 314 ; C = 51 + 314 − 213 ; D = 51 + 213 − 314 ; D = 51 + 213 − 314 E = 51 − 314 − 213 ; E = 51 − 314 + 213 F = 51 − 213 − 314. V ậ y A = F ; B = E = D
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\frac{217-x}{207}+\frac{215-x}{209}+\frac{213-x}{211}+\frac{211-x}{213}+4=0\)
\(\Leftrightarrow\)\(\left(\frac{217-x}{207}+1\right)+\left(\frac{215-x}{209}+1\right)+\left(\frac{213-x}{211}+1\right)+\left(\frac{211-x}{213}+1\right)=0\)
\(\Leftrightarrow\)\(\frac{424-x}{207}+\frac{424-x}{209}+\frac{424-x}{211}+\frac{424-x}{213}=0\)
\(\Leftrightarrow\)\(\left(424-x\right)\left(\frac{1}{207}+\frac{1}{209}+\frac{1}{211}+\frac{1}{213}\right)=0\)
\(\Leftrightarrow\)\(424-x=0\) (do 1/207 + 1/209 + 1/211 + 1/213 # 0)
\(\Leftrightarrow\)\(x=424\)
Vậy...
![](https://rs.olm.vn/images/avt/0.png?1311)
= -28 + 16 + (-213) + (-28) + (-213)
= 16 + [-2(28+213)]
= 16 + (-2*241)
= 16 + (-482)
= -466
`@` `\text {Ans}`
`\downarrow`
`-28 + [16 + (-213)] + (-28) + (-213)`
`= -28 + 16 - 213 - 28 - 213`
`= (-28-28) + (-213 - 213) + 16`
`= -56 - 426 + 16`
`= -482 + 16`
`= -466`