a) 𝟕𝟎𝟑 − 𝟏𝟒𝟎: (𝟒𝟐 + 𝟐𝟖) − 𝟏𝟕^𝟔 . 𝟏𝟕^𝟗 : 𝟏𝟕^𝟏𝟑
b) 𝟑𝟔. 𝟓𝟓 − 𝟏𝟖𝟓. 𝟏𝟏 + 𝟏𝟐𝟏. 𝟓
c) 𝟏𝟏𝟓𝟐 − (𝟑𝟕𝟒 + 𝟏𝟏𝟓𝟐) + (−𝟔𝟓 + 𝟑𝟕𝟒)
d) [𝟓𝟑 + (−𝟕𝟔)] − [−𝟕𝟔 − (−𝟓𝟑)]
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![](https://rs.olm.vn/images/avt/0.png?1311)
a. C = 12 . (-47) + 12 . (-19) + (-66) . 88
C = 12 . [-47 + (-19)] + (-66) . 88
C = 12 . (-66) + (-66) . 88
C = (-66) . (12 + 88)
C = -66 . 100
C = -6 600
b. D = (-135) . 29 - 13 . 135 + 42 . (-65)
D = 135 . (-29) - 13 . 135 + 42 . (-65)
D = 135 . [(-29) - 13] + 42 . (-65)
D = 135 . (-42) + 42 . (-65)
D = -135 . 42 + 42 . (-65)
D = 42 . [-135 - (-65)]
D = 42 . (-70)
D = -2940
![](https://rs.olm.vn/images/avt/0.png?1311)
1) Viết tập hợp sau bằng cách liệt kê các phần tử của nó:
a) 𝑨 = {𝒙 ∈ 𝒁|−𝟓 < 𝒙 ≤ 𝟏}
→ \(A=\left\{-4;-3;-2;-1;0;1\right\}\)
b) 𝑩 = {𝒙 ∈ 𝒁| − 𝟑 ≤ 𝒙 ≤ 𝟎}
→ \(B=\left\{-3;-2;-1;0\right\}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Lời giải:
a. $7^{2x-6}=49=7^2$
$\Rightarrow 2x-6=2$
$2x=8$
$x=4$
b.
$105-(135-7x):9=97$
$(135-7x):9=105-97=8$
$135-7x=8.9=72$
$7x=135-72=63$
$x=63:7=9$
c.
$3^{x-3}-3^2=2.3^2$
$3^{x-3}=3^2+2.3^2=3^2(1+2)=3^3$
$\Rightarrow x-3=3$
$\Rightarrow x=6$
d.
$275-(113+x)+63=158$
$338-(113+x)=158$
$113+x=338-158=180$
$x=180-113=67$
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(\dfrac{4}{5}\) x ( \(\dfrac{5}{4}\) - \(\dfrac{5}{7}\) )
= \(\dfrac{4}{5}\) x \(\dfrac{5}{4}\) - \(\dfrac{4}{5}\) x \(\dfrac{5}{7}\)
= 1 - \(\dfrac{4}{7}\)
= \(\dfrac{3}{7}\)
b) \(\dfrac{5}{8}\) x \(\dfrac{9}{7}\) + \(\dfrac{5}{8}\) x \(\dfrac{5}{7}\)
= \(\dfrac{5}{8}\) x ( \(\dfrac{9}{7}\) + \(\dfrac{5}{7}\) )
= \(\dfrac{5}{8}\) x 2
\(\dfrac{5}{4}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Đổi : \(1\dfrac{1}{6}dm\text{=}\dfrac{7}{6}dm\)
Chu vi hình chữ nhật đó là :
\(\left(\dfrac{7}{6}+\dfrac{2}{3}\right)\times2\text{=}\dfrac{11}{3}\left(dm\right)\)
đs.......
Chu vi HCN:
\(2\times\left(1\dfrac{1}{6}+\dfrac{2}{3}\right)=2\times\left(\dfrac{7}{6}+\dfrac{2}{3}\right)=2\times\dfrac{7+2\times2}{6}=2\times\dfrac{11}{6}=\dfrac{11}{3}\left(m\right)\\ Đ.số:\dfrac{11}{3}m\)
\(a,=703-140:70-17^2=703-2-289=412\\ b,=36.5.11-37.5.11+11.11.5=11.5(36-37+11)=55.10=550\\ c,=1152-374-1152-65+374=-65\\ d,=53-76+76-53=0\)