\(\frac{6^2}{43}=\frac{36}{43}\)

\(2.5^2=2.25=50\)

Vậy biểu thức có kết quả là:\(\frac{36}{43}+50\)

\(76-\left\{2\cdot\left[2\cdot5^2-\left(31-2\cdot3\right)\right]\right\}\)

\(=76-\left\{2\cdot\left[2\cdot25-\left(31-6\right)\right]\right\}\)

\(=75-\left[2\cdot\left(50-25\right)\right]\)

\(=76-\left(2\cdot25\right)\)

\(=76-50\)

\(=26\)

____________________

\(6^2\cdot10:\left\{780:\left[10^3-\left(2\cdot5^3+35\cdot14\right)\right]\right\}\)

\(=36\cdot10:\left\{780:\left[1000-\left(2\cdot125+490\right)\right]\right\}\)

\(=360:\left\{780:\left[1000-\left(250+490\right)\right]\right\}\)

\(=360:\left[780:\left(1000-740\right)\right]\)

\(=360:\left(780:260\right)\)

\(=360:3\)

\(=120\)

a: =76-{2*[2*25-31+6]}

=76-{2*[50-31+6]}

=76-2*25

=76-50=26

b: \(=360:\left\{\dfrac{780}{1000-2\cdot125-490}\right\}\)

\(=360:\dfrac{780}{260}\)

=360/3=120

6²:4.3+2.5²

=36:4.3+2.25

=9.3+50

=27+50

=77

Vậy GTBT=77

số đó là

77

ai k mình mình k 

lại cho

mình ko nói dối nửa lời

=77 đó

6²:4.3+2.5²

= 36 : 4 . 3 + 2.25

= 9.3 + 50

= 27 + 50

= 77

đáp số:77

6²:4.3+2.5²=36:4.3+2.25=9.3+50=27+50=77

\(6^2.2^2.5:\left[3.12-\left(2x-6\right)\right]=2^3.5\)

\(\Rightarrow36.4.5:\left[36-\left(2x-6\right)\right]=8.5\)

\(\Rightarrow720:\left[36-\left(2x-6\right)\right]=40\)

\(\Rightarrow36-\left(2x-6\right)=720:40=18\)

\(\Rightarrow2x-6=36-18=18\)

\(\Rightarrow2x=18+6=24\)

\(\Rightarrow x=24:2=12\)

Sửa đề: \(\dfrac{6}{2\cdot5}+\dfrac{6}{5\cdot8}+...+\dfrac{6}{62\cdot65}\)

\(=2\left(\dfrac{3}{2\cdot5}+\dfrac{3}{5\cdot8}+...+\dfrac{3}{62\cdot65}\right)\)

=3(1/2-1/5+1/5-1/8+...+1/62-1/65)

=3*63/130=189/130

Ta có :

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(1)

Từ (1), suy ra:

Vậy

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Ta có :

Đặt

(1)

Từ (1), suy ra:

Vậy

~ Học tốt ~