1+2-3-4+5+6-7-8+9+................+33

=1+(2-3-4+5)+(6-7-8+9)+............+(30-31-32+33)

=1+0+0+..............+0

=1

Cảm ơn nha ! Kết bạn với tớ nhé!

1+2-3-3+5+6-7-8+9+10-11-12+13+...............+33

= 1 + ( 2-3-4+5)+(6-7-8+9)+......+(30-31-32+33)

=1

`-3/7xx15/13-3/7xx11/13-3/7`

`=-3/7xx(15/13+11/13+1)`

`=-3/7xx3`

`=-9/7`

a: =308-117

=191

a) \(\dfrac{7}{30}+\dfrac{\left(-12\right)}{37}+\dfrac{23}{30}+\dfrac{\left(-25\right)}{37}=\left(\dfrac{7}{30}+\dfrac{23}{30}\right)+\left(\dfrac{-12}{37}+\dfrac{-25}{37}\right)=1+\left(-1\right)=0\)

b) \(\dfrac{5}{7}\cdot\dfrac{5}{11}+\dfrac{5}{7}\cdot\dfrac{2}{11}-\dfrac{5}{7}\cdot\dfrac{14}{11}=\dfrac{5}{7}\cdot\left(\dfrac{5}{11}+\dfrac{2}{11}-\dfrac{14}{11}\right)=\dfrac{5}{7}\cdot\left(-\dfrac{7}{11}\right)=-\dfrac{5}{11}\)

c) \(\dfrac{\left(-5\right)}{7}\cdot\dfrac{3}{13}-\dfrac{5}{7}\cdot\dfrac{10}{13}+1\dfrac{5}{7}=\dfrac{5}{7}\cdot\dfrac{-3}{13}-\dfrac{5}{7}\cdot\dfrac{10}{13}+\dfrac{12}{7}=\dfrac{5}{7}\cdot\left(\dfrac{-3}{13}-\dfrac{10}{13}\right)+\dfrac{12}{7}=\dfrac{5}{7}\cdot\left(-1\right)+\dfrac{12}{7}=\left(-\dfrac{5}{7}\right)+\dfrac{12}{7}=\dfrac{7}{7}=1\)

\(A=\frac{10}{5.7}+\frac{10}{7.9}+\frac{10}{9.11}+...+\frac{10}{33.35}\)

\(\Rightarrow A=10.\left(\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}+...+\frac{1}{33.35}\right)\)

Đặt \(B=\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}+...+\frac{1}{33.35}\)

\(\Rightarrow2B=\frac{2}{5.7}+\frac{2}{7.9}+\frac{2}{9.11}+...+\frac{2}{33.35}\)

\(\Rightarrow2B=\frac{1}{5}-\frac{1}{35}=\frac{6}{35}\)

\(\Rightarrow B=\frac{3}{35}\)

\(\Rightarrow A=10.\frac{3}{35}=\frac{30}{35}=\frac{6}{7}\)

_Học tốt_

6/7 nha .Tính mãi mới ra

Thank you bạn nha .Bạn kết bạn với mình nhé,mình cũng là fan của BTS

a)\(315-64:2^3\)

\(=315-2^6:2^3\)

\(=315-8=307\)

b)\(7^2.33+7^2.67\)

\(=7^2\left(33+67\right)\)

\(=7^2.100=4900\)

a) \(315-64\div2^3=315-2^6\div2^3=315-2^{6-3}=315-2^3=315-8=307\)

b) \(7^2.33+7^2.67=7^2.\left(33+67\right)=7^2.100=49.100=4900\)

a, = 315 - \(2^6:2^3\)

= 315 - 2\(^{6-3}\)

= 315 - \(2^3\)

= 315 - 8

= 307

(7/111 - 4/33 + 9/37).(1/2 - 1/3 -1/6)

= (7/111 - 4/33 + 9/37).0

= 0

(7/111 - 4/33 + 9/37).(1/2 - 1/3 - 1/6)

= (7/111 - 4/33 + 9/37).0

= 0