Sửa đề: |x-2|-3,75=(0,5)^2
=>|x-2|=3,75+0,25=4
=>x-2=4 hoặc x-2=-4
=>x=-2 hoặc x=6
Sửa đề: |x-2|-3,75=(0,5)^2
=>|x-2|=3,75+0,25=4
=>x-2=4 hoặc x-2=-4
=>x=-2 hoặc x=6
Bài 8:
b)\(\left(\dfrac{-4}{3}\right)+\left(\dfrac{-2}{5}\right)+\left(\dfrac{-3}{2}\right)\)
c) \(\dfrac{4}{5}-\left(\dfrac{-2}{7}\right)-\dfrac{-7}{10}\)
d) \(\dfrac{2}{3}-\left[\left(\dfrac{-7}{4}\right)-\left(\dfrac{1}{2}+\dfrac{3}{8}\right)\right]\)
\(\dfrac{25^2.4^2}{5^5.\left(-2\right)^5}=\dfrac{\left(25.4\right)^2}{\left(5.\left(-2\right)\right)^5}=\dfrac{\left(100\right)^2}{\left(-10\right)^5}=\dfrac{1}{-10}\)
Tìm x biết
a)\(\dfrac{2}{\left(x+2\right)\times\left(x+4\right)}+\dfrac{4}{\left(x+4\right)\times\left(x+8\right)}+\dfrac{6}{\left(x+8\right)\times\left(x+14\right)}=\dfrac{x}{\left(x+2\right)\times\left(x+14\right)}\)
a) \(\dfrac{3}{7}+\left(-\dfrac{5}{2}\right)+\left(-\dfrac{3}{5}\right)\)
b) \(\left(-\dfrac{4}{3}\right)+\left(-\dfrac{2}{5}\right)+\left(-\dfrac{3}{2}\right)\)
Tính
a) \(\dfrac{3}{7}+\left(-\dfrac{5}{2}\right)+\left(-\dfrac{3}{5}\right)\) ; b) \(\left(-\dfrac{4}{3}\right)+\left(-\dfrac{2}{5}\right)+\left(-\dfrac{3}{2}\right)\);
c) \(\dfrac{4}{5}-\left(-\dfrac{2}{7}\right)-\dfrac{7}{10}\) ; d) \(\dfrac{2}{3}-\left[\left(\dfrac{-7}{4}\right)-\left(\dfrac{1}{2}+\dfrac{3}{8}\right)\right]\).
\(\left(\dfrac{1}{2}.x-\dfrac{2}{3}\right)-\left(\dfrac{1}{3}.x-1\right)=\left(x-3\right)-\left(x-1\right)\)
C/m các đẳng thức sau:
a) \(\dfrac{1}{a\left(a+1\right)}=\dfrac{1}{a}-\dfrac{1}{a+1}\)
b) \(\dfrac{2}{a\left(a+1\right)\left(a+2\right)}=\dfrac{1}{a\left(a+1\right)}-\dfrac{1}{\left(a+1\right)\left(a+2\right)}\)
Tinh:
\(\dfrac{7}{8}.\left(\dfrac{2}{12}+\dfrac{4}{10}\right)\)
\(\dfrac{3}{2}-\dfrac{5}{6}:\left(\dfrac{1}{2}\right)^2+\sqrt{4}\)
\(\dfrac{15}{34}+\dfrac{7}{21}+\dfrac{19}{34}-1\dfrac{15}{17}+\dfrac{2}{3}\)
\(\left(-2\right)^3.\left(\dfrac{3}{4}-0,25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(16\dfrac{2}{7}:\left(-\dfrac{3}{5}\right)+28\dfrac{2}{7}:\left(-\dfrac{3}{5}\right)\)
\(\left(1-\dfrac{1}{2}\right)\left(1-\dfrac{1}{3}\right)\left(1-\dfrac{1}{4}\right)...\left(1-\dfrac{1}{2022}\right)\)