4 * 5 = ? ai nhanh m t
Tìm x , biết :
( 3 4/5 - 2 . x ) . 1 1/3 = 5 5/7
Ai nhanh nhất mik tick
\((3\frac{4}{5}-2x).1\frac{1}{3}=5\frac{5}{7}\)
\(3\frac{4}{5}-2x\)=\(4\frac{2}{7}\)
2x=\(\frac{-17}{35}\)
x=\(\frac{-17}{70}\)
Vậy x=\(\frac{-17}{70}\)
Tính nhanh
1/2-2/3+3/4-4/5+5/6-6/7-5/6+4/5-3/4
ai giúp mình với mk tick cho!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2) Tìm x:
a)(-5)^2 - (5x - 3)= 4^3
b)3x -17=x+3
c)5^x +5^x+2 = 650
AI NHANH MÌNH TICK CHO :)
2
a,\(\left(-5\right)^2-\left(5x-3\right)=4^3\)
=>25-5x+3=64
=>25+3-64=5x
=>-36=5x
=>x=-36:5
=>x=-7,2
b,3x-17=x+3
=>3x-x=17+3
=>2x=20
=>x=20:2
=>x=10
c,\(5^x+5^{x+2}=650\)
=>\(5^x+5^x.5^2=650\)
=>\(5^x+5^x.25=650\)
=>\(5^x.\left(1+25\right)=650\)
=>\(5^x.26=650\)
=>\(5^x=650:26\)
=>\(5^x\)=25
=>\(5^x=5^2\)
=>x=2
Tính nhanh
1/2-2/3+3/4-4/5+5/6-6/7+7/8+6/7-5/6+4/5-3/4+2/3-1/2
ai giúp mình với mk tick cho!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
\(\dfrac{1}{2}-\dfrac{2}{3}+\dfrac{3}{4}-\dfrac{4}{5}+\dfrac{5}{6}-\dfrac{6}{7}+\dfrac{7}{8}+\dfrac{6}{7}-\dfrac{5}{6}+\dfrac{4}{5}-\dfrac{3}{4}+\dfrac{2}{3}-\dfrac{1}{2}\)
\(=\left(\dfrac{1}{2}-\dfrac{1}{2}\right)+\left(-\dfrac{2}{3}+\dfrac{2}{3}\right)+....+\left(-\dfrac{6}{7}+\dfrac{6}{7}\right)+\dfrac{7}{8}\)
\(=\dfrac{7}{8}\)
Chúc bạn học tốt!!!
\(\dfrac{1}{2}-\dfrac{2}{3}+\dfrac{3}{4}-\dfrac{4}{5}+\dfrac{5}{6}-\dfrac{6}{7}+\dfrac{7}{8}+\dfrac{6}{7}-\dfrac{5}{6}+\dfrac{4}{5}-\dfrac{3}{4}+\dfrac{2}{3}-\dfrac{1}{2}\)
= \((\dfrac{1}{2}-\dfrac{1}{2})+(-\dfrac{2}{3}+\dfrac{2}{3})+...+(-\dfrac{6}{7}+\dfrac{6}{7})+\dfrac{7}{8}\)
=\(\dfrac{7}{8}\)
1/2-2/3+3/4-4/5+5/6-6/7+7/8+6/7-5/6+4/5-3/4+2/3-1/2
= \(\dfrac{7}{8}\)
Chuyên mục tính nhẩm tính nhanh lớp 6 [Chú ý: Ôn lại tính nhanh, tính nhẩm nha]
a, 15*5+75*5+5*3+5*7=?
b,2*200+4*100+4*50+(125*8)=?
c, 125*20*8*2*100*5=?
Tính đầy đủ nha
Ai nhanh ai đúng= 1 tick và 2 like nha :)
Lấy 2 bn nhanh nhất
a) \(15\cdot5+75\cdot5+5\cdot3+5\cdot7\)
\(=5\left(15+75\right)+5\left(3+7\right)\)
\(=5\cdot90+5\cdot10=5\left(90+10\right)=5\cdot100=500\)
b) \(2\cdot200+4\cdot200+4\cdot50+125\cdot8\)
\(=2.2.100+4\cdot200+4\cdot50+125\cdot2\cdot4\)
\(=4\left(100+200+50+250\right)\)
\(=4\cdot600=2400\)
c) \(125\cdot20\cdot80\cdot2\cdot100\cdot5\)
\(=\left(125\cdot8\right)\cdot\left(2\cdot5\right)\cdot100\cdot20\)
\(=1000\cdot10\cdot100\cdot20\)
\(=20000000\)
Tìm x :(x-2)(2x +1)-5(x +3)=2x(x-3)+4(1+2x)-2(1+x)
Ai nhanh mình tick lời giải chi tiết nha
\(\left(x-2\right)\left(2x+1\right)-5\left(x+3\right)=2x\left(x-3\right)+4\left(1+2x\right)-2\left(1+x\right)\)
\(2x^2+x-4x-2-5x-15=2x^2-6x+4+8x-2-2x\)
\(x-4x-2-5x-15=-6x+4+8x-2-2x\)
\(\Rightarrow-8x-17=2\)
\(-8x=19\Rightarrow x=-\dfrac{19}{8}\)
Vậy \(x=-\dfrac{19}{8}\)
\(\left(x-2\right)\left(2x+1\right)-5\left(x+3\right)=2x\left(x-3\right)+4\left(1+2x\right)-2\left(1+x\right)\)
\(\Rightarrow2x^2+x-4x-2-5x-15-2x^2+6x-4-8x+2+2x=0\\ \Leftrightarrow-8x-19=0\\ \Leftrightarrow-8x=19\\ \Leftrightarrow x=-\dfrac{19}{8}\)
Tìm x để B = 2x + 3 / 5x - 1 là số nguyên
Tìm giá trị lớn nhất của C = 2|x| + 3 / 5|x| - 4
Ai giải nhanh, đúng mk tick cho
Tính :
a) b)
\(\dfrac{\dfrac{5}{7}+\dfrac{5}{9}+\dfrac{5}{11}}{\dfrac{25}{7}+\dfrac{25}{7}+\dfrac{25}{11}}\) \(\dfrac{4+\dfrac{4}{73}-\dfrac{4}{115}}{5+\dfrac{5}{73}-\dfrac{1}{23}}\)
Mong mọi người sẽ trả lời nhanh ai nhanh mình sẽ cho 2 like luôn
dễ lắm bạn ơi bọn mình học rùi
bn lấy tử số của từng mỗi rồi chia cho mẫu của từng cái rồi rút gọn lafd ra
\(\dfrac{\dfrac{5}{7}+\dfrac{5}{9}+\dfrac{5}{11}}{\dfrac{25}{7}+\dfrac{25}{9}+\dfrac{25}{11}}\cdot\dfrac{4+\dfrac{4}{73}-\dfrac{4}{115}}{5+\dfrac{5}{73}-\dfrac{1}{23}}\)
=\(\dfrac{5\cdot\left(\dfrac{1}{7}+\dfrac{1}{9}+\dfrac{1}{11}\right)}{25\left(\dfrac{1}{7}+\dfrac{1}{9}+\dfrac{1}{11}\right)}\cdot\dfrac{4\left(1+\dfrac{1}{73}+\dfrac{1}{115}\right)}{5+\dfrac{5}{73}-\dfrac{5}{115}}\)
=\(\dfrac{5}{25}\cdot\dfrac{4\left(1+\dfrac{1}{73}-\dfrac{1}{115}\right)}{5\left(1+\dfrac{1}{73}-\dfrac{1}{115}\right)}\)
=\(\dfrac{1}{5}\cdot\dfrac{4}{5}\)=\(\dfrac{4}{25}\)
\(\dfrac{\dfrac{5}{7}+\dfrac{5}{9}+\dfrac{5}{11}}{\dfrac{25}{7}+\dfrac{25}{9}+\dfrac{25}{11}}\cdot\dfrac{4+\dfrac{4}{73}-\dfrac{4}{115}}{5+\dfrac{5}{73}-\dfrac{1}{23}}\)
\(=\dfrac{\dfrac{5}{7}+\dfrac{5}{9}+\dfrac{5}{11}}{5\left(\dfrac{5}{7}+\dfrac{5}{9}+\dfrac{5}{11}\right)}\cdot\dfrac{4+\dfrac{4}{73}-\dfrac{4}{115}}{5+\dfrac{5}{73}-\dfrac{5}{115}}\)
\(=\dfrac{1}{5}\cdot\dfrac{4\left(1+\dfrac{1}{73}-\dfrac{1}{115}\right)}{5\left(1+\dfrac{1}{73}-\dfrac{1}{115}\right)}\)
\(=\dfrac{1}{5}\cdot\dfrac{4}{5}=\dfrac{4}{25}\)
Tìm A: 6a+5 chia hết cho 3a-1
Nhanh lên,ai làm nhanh tớ cho 3 tick
6a + 5 ⋮ 3a-1
=> 6a - 2 + 7 ⋮ 3a-1
=> 2. (3a - 1) + 7 ⋮ 3a-1
Có: 2. (3a - 1) ⋮ 3a - 1 => Để 6a + 5 ⋮ 3a-1 thì:
7 ⋮ 3a - 1
=> 3a - 1 ∈ Ư(7)
=> 3a - 1 ∈ {1; -1; 7; -7}
=> 3a ∈ {2; 0; 8; -6}
Mà: 3a ⋮ 3 => 3a ∈ {0; -6}
=> a ∈ {0; -2}
Vậy: ................
6a+5⋮3a-1
=>6a-3+8⋮3a-1
=>2(3a-1)+8⋮3a-1
=>8⋮3a-1[vì 3a-1⋮3a-1 nên 2(3a-1)⋮3a-1]
=>3a-1∈Ư(8)={1;2;4;8;-1;-2;-4;-8}
Đến đây làm tiếp đc hơm ??
Làm đc thì tự làm nốt nhé bae