Tìm x biết:
a, .(x-3 ) + (x-2) +(x-1) +...+ 10 +11= 11
b, 3x + 3x+1 +3x+2 =351
c, [-7/4 . x ] . [33/12 + 3333/2020 +333333/303030 +33333333 / 42424242] = 22
tìm x biết
-7/4 nhân x nhân (33/12+3333/2020+333333/303030+33333333/42424242)=22
Tìm x biết: -7/4x.(33/12+3333/2020+333333/303030+33333333/42424242)=22
Kết quả : Viết lại biểu thức đã cho
=> -7/4x . ( 33/12 + 33/20 + 33/30 + 33/42 ) = 22
-7/4x . 33 . ( 1/12 + 1/20 + 1/30 + 1/42 ) = 22
-231/4x . ( 1/3 . 4 + 1/ 4. 5 + 1/5 . 6 + 1/ 6. 7 ) = 22
-231/4x . ( 1/3 - 1/4 + 1/4 - 1/5 + 1/5 - 1/6 + 1/6 - 1/7 ) = 22
-231/4x . ( 1/3 - 1/7 ) = 22
-231/4x . 4/21 = 22
-11x = 22
x = 22 : -11
x = -2
Vậy x = -2
Tính nhanh : P= -7/4 x (33/12 + 3333/2020 + 333333/303030 + 33333333/42424242)
\(P=-\frac{7}{4}.\left(\frac{33}{12}+\frac{3333}{2020}+\frac{333333}{303030}+\frac{33333333}{42424242}\right)\)
\(P=-\frac{7}{4}.\left(\frac{33}{12}+\frac{33.101}{20.101}+\frac{33x10101}{30x10101}+\frac{33x1010101}{42x1010101}\right)\)
\(P=-\frac{7}{4}.\left(\frac{33}{12}+\frac{33}{20}+\frac{33}{30}+\frac{33}{42}\right)\)
\(P=-\frac{7}{4}.\left(\frac{11}{4}+\frac{33}{20}+\frac{11}{10}+\frac{11}{14}\right)\)
\(P=-\frac{77}{8}.\left(\frac{1}{6}+\frac{3}{10}+\frac{1}{15}+\frac{1}{21}\right)=-\frac{77}{8}.\frac{35+63+14+10}{210}=-\frac{11x122}{8x30}\)
\(P=-\frac{671}{120}\)
P = -7/4 x (33/12 + 3333/2020 + 333333/303030 + 33333333/42424242)
= -7/4 x (33/12 + 33/20 + 33/30 + 33/42)
= -7/4 x [33 x (1/12 + 1/20 + 1/30 + 1/42)]
= -7/4 x [33 x (35/420 + 21/420 + 14/420 + 10/420)]
= -7/4 x (33 x 80/420)
= -7/4 x 33 x 4/21
= -7/4 x 4/21 x 33 (= -7x4 / 4x21 x33)
= -7/21 x 33 (= -7x33 / 21 = -1x7x3x11 / 3x7)
= -11/1
= -11
Đáp số P = -11
Các số gạch đi là do rút gọn phân số nhé!!!
tìm x:
a) -7/4 . x ( 33/ 12 + 3333/2020 + 333333/303030 + 33333333/42424242)
b) 1+5 +9 + 13 + 15 +...+x = 501501
Tìm x
1) \(\frac{-7}{4}x\cdot\left(\frac{33}{12}+\frac{3333}{2020}+\frac{333333}{303030}+\frac{33333333}{42424242}\right)=22\)
2) \(\frac{1}{2016}:2015\cdot x=\frac{-1}{2015}\)
a) 74x.(3312+33332020+333333303030+3333333342424242)=32\frac{7}{4}x.\left(\frac{33}{12}+\frac{3333}{2020}+\frac{333333}{303030}+\frac{33333333}{42424242}\right)=3247x.(1233+20203333+303030333333+4242424233333333)=32
74x.(3312+3320+3330+3342)=32\frac{7}{4}x.\left(\frac{33}{12}+\frac{33}{20}+\frac{33}{30}+\frac{33}{42}\right)=3247x.(1233+2033+3033+4233)=32
74x.(333.4+334.5+335.6+336.7)=32\frac{7}{4}x.\left(\frac{33}{3.4}+\frac{33}{4.5}+\frac{33}{5.6}+\frac{33}{6.7}\right)=3247x.(3.433+4.533+5.633+6.733)=32
74x.33.(13−14+14−15+15−16+16−17)=32\frac{7}{4}x.33.\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}\right)=3247x.33.(31−41+41−51+51−61+61−71)=32
74x.33.(13−17)=32\frac{7}{4}x.33.\left(\frac{1}{3}-\frac{1}{7}\right)=3247x.33.(31−71)=32
74x.33⋅421=32\frac{7}{4}x.33\cdot\frac{4}{21}=3247x.33⋅214=32
b) 13+16+110+115+...+2x.(x−1)=20072009\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+\frac{1}{15}+...+\frac{2}{x.\left(x-1\right)}=\frac{2007}{2009}31+61+101+151+...+x.(x−1)2=20092007
26+212+220+230+...+2(x−1).x=20072009\frac{2}{6}+\frac{2}{12}+\frac{2}{20}+\frac{2}{30}+...+\frac{2}{\left(x-1\right).x}=\frac{2007}{2009}62+122+202+302+...+(x−1).x2=20092007
22.3+23.4+24.5+25.6+...+2(x−1).x=20072009\frac{2}{2.3}+\frac{2}{3.4}+\frac{2}{4.5}+\frac{2}{5.6}+...+\frac{2}{\left(x-1\right).x}=\frac{2007}{2009}2.32+3.42+4.52+5.62+...+(x−1).x2=20092007
2.(12−13+13−14+14−15+15−16+...+1x−1−1x)=200720092.\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+...+\frac{1}{x-1}-\frac{1}{x}\right)=\frac{2007}{2009}2.(21−31+31−41+41−51+51−61+...+x−11−x1)=20092007
2.(12−1x)=200720092.\left(\frac{1}{2}-\frac{1}{x}\right)=\frac{2007}{2009}2.(21−x1)=20092007
1−2x=200720091-\frac{2}{x}=\frac{2007}{2009}1−x2=20092007
2x=22009\frac{2}{x}=\frac{2}{2009}x2=20092
=> x = 2009
a) \frac{7}{4}x.\left(\frac{33}{12}+\frac{3333}{2020}+\frac{333333}{303030}+\frac{33333333}{42424242}\right)=3247x.(1233+20203333+303030333333+4242424233333333)=32
\frac{7}{4}x.\left(\frac{33}{12}+\frac{33}{20}+\frac{33}{30}+\frac{33}{42}\right)=3247x.(1233+2033+3033+4233)=32
\frac{7}{4}x.\left(\frac{33}{3.4}+\frac{33}{4.5}+\frac{33}{5.6}+\frac{33}{6.7}\right)=3247x.(3.433+4.533+5.633+6.733)=32
\frac{7}{4}x.33.\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}\right)=3247x.33.(31−41+41−51+51−61+61−71)=32
\frac{7}{4}x.33.\left(\frac{1}{3}-\frac{1}{7}\right)=3247x.33.(31−71)=32
\frac{7}{4}x.33\cdot\frac{4}{21}=3247x.33⋅214=32
đến đây thì bn tự lm đk r
-7/4x.(33/12+3333/2020+333333/303030+33333333/42424242)=22
7/4.( 33/12 + 3333/2020 + 333333/303030 + 33333333/42424242) = ?
\(\frac{7}{4}\left(\frac{33}{12}+\frac{3333}{2020}+\frac{333333}{303030}+\frac{33333333}{42424242}\right)\)
=\(\frac{7}{4}\left(\frac{33}{12}+\frac{33}{20}+\frac{33}{30}+\frac{33}{42}\right)\)
=\(\frac{7}{4}.33\left(\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}\right)\)
=\(\frac{231}{4}\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}\right)\)
=\(\frac{231}{4}\left(\frac{1}{3}-\frac{1}{7}\right)\)
=\(\frac{231}{4}.\frac{4}{21}\)
= 11
-7/4 .(33/12+3333/2020+333333/303030+33333333/42424242)
\(\dfrac{-7}{4}.\left(\dfrac{33}{12}+\dfrac{3333}{2020}+\dfrac{333333}{303030}+\dfrac{33333333}{42424242}\right)\)
\(=\dfrac{-7}{4}.\left(\dfrac{33}{12}.\dfrac{33.101}{20.101}.\dfrac{33.10101}{30.10101}.\dfrac{33.1010101}{42.1010101}\right)\)
\(=\dfrac{-7}{4}.\left(\dfrac{33}{12}.\dfrac{33}{20}.\dfrac{33}{30}.\dfrac{33}{42}\right)\)
\(=\dfrac{-7}{4}.33.\left(\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+\dfrac{1}{42}\right)\)
\(=\dfrac{-7}{4}.33.\left(\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}\right)\)
\(=\dfrac{-7}{4}.33.\left(\dfrac{1}{3}-\dfrac{1}{7}\right)\)
\(=\dfrac{-7}{4}.33.\dfrac{4}{21}\)
\(=33.\dfrac{-1}{3}\)
\(=11\)
xl nhé kết quả là -11 mk viết thiếu dấu -
I.Tìm x, biết :
a) -(7/4) x (33/12 + 3333/2020 + 333333/303030 + 33333333/42424242)=22
b) 137x137x chia hết cho 13
II. So sánh :
a)A= 1/2.3/4.5/6. ... . 99/100 và B= 2/3.4/5.6/7. ... . 100/101
b) Cho : A=1/1.2+1/3.4+1/5.6+...+1/59.60
B=1/31+1/32+1/33+...+1/60
Hãy so sánh A và B ?
III. Cho các góc nhọn AOB và AOC có số đo theo thứ tự bằng 80o và 40o. Vẽ tia OE nằm giữa hai tia OA,OB sao cho BOE=60o. Tia OE là tia phân giác của góc nào ? Vì sao ?
IV.Tìm số nguyên n sao cho C= 2n+11 / n-1 cũng là số nguyên
V.Biết rằng số tự nhiên n chỉ có đúng 3 ước số. Hãy chững tỏ rằng số tự nhiên n đó là một số chính phương.
VI.Tìm các số tự nhiên x,y thỏa mãn x^2+x-89=5^y