-0.8\(\sqrt{\left(-0.125\right)^{2\left[\right]}}\)
a)\(-0.8\sqrt{\left(-0.125\right)^2}\) b)\(\sqrt{\left(-2\right)^6}\)
a) \(-0.8\sqrt{\left(-0.125\right)^2}=-0.8\left|-0.125\right|=-0.8\times0.125=0,1\)
b) \(\sqrt{\left(-2\right)^6}=\sqrt{2^6}=\sqrt{\left(2^3\right)^2}=\left|8\right|=8\)
Bài 1: Thực hiện các phép tính sau:
a) \(-0.8\sqrt{\left(-0,125\right)^2}\) b) \(\sqrt{\left(-2\right)^6}\)
c) \(\sqrt{\left(\sqrt{3}-2\right)^2}\) d) \(\sqrt{\left(2\sqrt{2}-3\right)^2}\)
Hộ mk vs ạ :<
a) \(-0,8\sqrt{\left(-0,125\right)^2}=-0,8.\left|-0,125\right|=-0.8.0,125=-\dfrac{1}{10}\)
b) \(\sqrt{\left(-2\right)^6}=\sqrt{\left(\left(-2\right)^3\right)^2}=\left|\left(-2\right)^3\right|=8\)
c) \(\sqrt{\left(\sqrt{3}-2\right)^2}=\left|\sqrt{3}-2\right|=2-\sqrt{3}\)
d) \(\sqrt{\left(2\sqrt{2}-3\right)^2}=\left|2\sqrt{2}-3\right|=3-2\sqrt{2}\)
so sánh A và B biết:
A=\(\left[0.8\cdot7+\left(0.8\right)^2\right]\cdot\left(1.25\cdot7-\frac{4}{5}\cdot1.25\right)-47.86\)
B=\(\frac{\left(1.09-0.29\right)\cdot\frac{5}{4}}{\left(18.9-16.65\right)\cdot\frac{8}{9}}\)
\(A=\left[0,8\cdot7+(0,8)^2\right]\cdot\left[1,25\cdot7-\frac{4}{5}\cdot1,25\right]-47,86\)
\(=0,8\cdot(7+0,8)\cdot1,25\cdot(7-0,8)-47,86\)
\(=0,8\cdot7,8\cdot1,25\cdot6,2-47,86\)
\(=48,36-47,86=0,5\)
\(B=\frac{(1,09-0,29)\cdot\frac{5}{4}}{(18,9-16,65)\cdot\frac{8}{9}}=\frac{0,8\cdot1,25}{2,25\cdot\frac{8}{9}}=\frac{1}{2}\)
\(A:B=0,5:\frac{1}{2}=\frac{1}{2}:\frac{1}{2}=\frac{1}{2}\cdot2=1\)
A gấp 1 lần B
??????????????????
5) \(\left(1+\dfrac{2}{3}-\dfrac{1}{4}\right).\left(0.8-\dfrac{3}{4}\right)^2\)
\(\left(1+\dfrac{2}{3}-\dfrac{1}{4}\right)\cdot\left(\dfrac{4}{5}-\dfrac{3}{4}\right)^2\)
\(=\dfrac{12+8-3}{12}\cdot\left(\dfrac{16-15}{20}\right)^2\)
\(=\dfrac{17}{12}\cdot\dfrac{1}{20^2}=\dfrac{17}{4800}\)
tính giá trị các biểu thức
a) \(\dfrac{\left(0.125\right)^5.\left(2,4\right)^5}{\left(-0,3\right)^5.\left(0,01\right)^3}\)
b) \(\left(-2\dfrac{3}{4}+\dfrac{1}{2}\right)^2\)
b) \(\left(-2\dfrac{3}{4}+\dfrac{1}{2}\right)^2\)
\(=\left(\dfrac{-11}{4}+\dfrac{1}{2}\right)^2\)
\(=\left(\dfrac{-11}{4}+\dfrac{2}{4}\right)^2\)
\(=\left(\dfrac{-9}{4}\right)^2\)
\(=\dfrac{81}{16}\)
A=\(\left(\frac{x-y}{\sqrt{x}-\sqrt{y}}+\frac{x\sqrt{x}+y\sqrt{y}}{y-x}\right):\left(\frac{\left(\sqrt{x}-\sqrt{y}\right)^2+\sqrt{xy}}{\sqrt{x}+\sqrt{y}}\right)\)
a) Rút gọn A
b)Tìm x,y để A có giá trị nhỏ nhất
c)So sánh A với \(\sqrt{A}\)
đ) Tính A khi x=1,8 y=0.8
Tìm x:
a) \(\dfrac{16}{3}:x=\dfrac{50}{12}\left(-0,06\right)\) b) \(2.x-1^3=-8\) c) \(\dfrac{\left(0.8\right)^5}{\left(0.4\right)^6}=x\)
d)\(0,944-2.x=3,268\) e)\(\sqrt{\dfrac{0,09}{25}=-\dfrac{4,7}{5}+x}\) g)\(\sqrt{5^2-3^2}=-\sqrt{81-x}\)
a) x = \(\dfrac{-64}{3}\)
b) x = -3,5
c) x = 80
d) x = -1.162
e) x = 0,9436
g) x \(\in\varnothing\)
a) 16/3 : x = -1/4
=> x = 16/3 : (-1/4)
=> x = 16/3 . (-4)
=> x = -64/3
Vậy x= -64/3
b)2x - 13 = -8
=> 2x = (-8) + 1
=> 2x = -7
=> x = -7/2
d) 0,944 - 2x = 3,268
=> 2x = 0,944 - 3,268
=> 2x = -2,324
=> x = (-2,324) : 2
=> x = -1,162
g) \(\sqrt{5^2-3^2}=-\sqrt{81-x}\)
=> \(\sqrt{25-9}\)= \(-\sqrt{81-x}\)
=> \(\sqrt{16}\)=\(-\sqrt{81-x}\)
=> 4=\(-\sqrt{81-x}\)
tới đây mik bí r hk bt lm nữa
a)\(\left(\frac{2}{3}+\frac{4}{5}+\frac{12}{7}\right)+\left(2^7.5^6-\frac{25^3}{\left(0.125\right)3}\right).\left(0.0001\right)^2\)
b) \(2\frac{1}{315}.\frac{1}{651}-\frac{1}{105}.3\frac{650}{651}-\frac{4}{315.651}+\frac{4}{105}\)
\(P=\left(\frac{\sqrt{x}-2}{x-1}-\frac{\sqrt{x}+2}{x+2\sqrt{x}+1}\right)\frac{\left(1-x\right)^2}{2}\)
\(P=\left(\frac{\sqrt{x}-2}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}-\frac{\sqrt{x}+2}{\left(\sqrt{x}+1\right)^2}\right)\frac{\left(1-x\right)^2}{2}\)
\(P=\left(\frac{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)-\left(\sqrt{x}+2\right)\left(\sqrt{x}-1\right)}{\left(x-1\right)\left(\sqrt{x}+1\right)}\right)\frac{\left(x-1\right)^2}{2}\)
\(P=\left(\frac{\left(x-\sqrt{x}-2\right)-\left(x+\sqrt{x}-2\right)}{\left(x-1\right)\left(\sqrt{x}+1\right)}\right)\frac{\left(x-1\right)^2}{2}\)
\(P=\frac{2\sqrt{x}}{\left(x-1\right)\left(\sqrt{x}+1\right)}\frac{\left(x-1\right)^2}{2}\)
\(P=\frac{\sqrt{x}\left(x-1\right)}{\sqrt{x}+1}=\sqrt{x}\left(\sqrt{x}-1\right)=x-\sqrt{x}\)