Tính giá trị của các biểu thức sau :
a/ \(A=\dfrac{1}{\sqrt{25}}+\dfrac{\sqrt{49}}{\sqrt{36}}-\dfrac{2}{\sqrt{100}}\)
b/ \(B=\sqrt{\dfrac{0,01}{1,21}}+3.\dfrac{2}{\sqrt{10^2}+2^2+40}-\dfrac{3}{4}\)
thực hiện phép tính
a, \(\dfrac{5}{6}+\left(\dfrac{-1}{2}\right)+\dfrac{3}{4}\)
b,\(\left(0,75-\dfrac{1}{3}\right):\dfrac{7}{15}\)
c,\(\dfrac{7}{12}-\dfrac{3}{4}.\dfrac{5}{6}\)
d,\(\left(2\dfrac{1}{3}+1\dfrac{3}{4}\right).\dfrac{12}{13}\)
Giúp mk với
a.(4x - 1)\(^2\) = ( 1 -4x)\(^2\)
b. \(\dfrac{x-100}{24}+\dfrac{x-98}{26}+\dfrac{x-96}{28}=3\)
Chứng minh rằng: \(\dfrac{1}{\sqrt{1}}+\dfrac{1}{\sqrt{2}}+\dfrac{1}{\sqrt{3}}+...+\dfrac{1}{\sqrt{100}}>10\)
Chung minh rang tong sau khong la so tu nhien :
A = \(\dfrac{1}{2^2}\) + \(\dfrac{1}{3^2}\) + \(\dfrac{1}{4^2}\) + ..........+ \(\dfrac{1}{100^2}\)
Thực hiện phép tính nhanh
a/\(\dfrac{3}{4}+\dfrac{1}{4}:\dfrac{-2}{3}-\left(-5\right)\)
b/\(12.\left(\dfrac{2}{3}-\dfrac{5}{6^{ }}\right)^2\)
c/\(3-6.\left(\dfrac{-6}{7}\right)^0+\left(\dfrac{1}{2}\right)^2:2\)
Cho:
A=\(\left(\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}+...+\dfrac{1}{2016}+\dfrac{1}{2017}\right)\)
B=\(\dfrac{2016}{1}+\dfrac{2015}{2}+\dfrac{2014}{3}+...+\dfrac{3}{2014}+\dfrac{2}{2015}+\dfrac{1}{2016}\)
Tính \(\dfrac{B}{A}\)
giúp mình nha, mình đang cần gấp gấp gấp lắm....!HELP ME!!!
Cho a,b,c khác 0 thỏa mãn:\(\dfrac{a.b+a.c}{2}=\dfrac{b.c+b.a}{3}=\dfrac{c.a+c.b}{4}\)CM \(\dfrac{a}{3}=\dfrac{b}{5}=\dfrac{c}{15}\)
Tìm x biết
1) \(\left|\dfrac{1}{4}\times x^2+\dfrac{1}{45}\right|+\dfrac{1}{5}=\dfrac{1}{4}\)
2) \(\left(x^2-3\right)\times x^2-2\times x\times\left(x^2-3\right)\)