Tính các tổng :
a) \(-11+y+7\)
b) \(x+22+\left(-14\right)\)
c) \(a+\left(-15\right)+62\)
Tính các biểu thức sau :
\(\dfrac{a.\left(7\cdot x^2+11\cdot y^2\right)}{\left(14\cdot x^{12}-11\cdot y^2\right)}.\left(\dfrac{x}{11}\right)=\left(\dfrac{y}{7}\right)\)
Bài 1: Thực hiện các phép tính dau bằng cách hợp lí
a. \(\frac{11}{225}-\frac{17}{18}-\frac{5}{7}+\frac{4}{9}+\frac{17}{14}\)
b. \(1-\frac{1}{2}+2-\frac{2}{3}+3-\frac{3}{4}+4-\frac{1}{4}-3-\frac{1}{3}-2-\frac{1}{2}-1\)
Bài 2: Tìm x biết
a. \(\frac{11}{13}-\left(\frac{5}{42}-x\right)=-\left(\frac{15}{28}-\frac{11}{13}\right)\)
b. \(\left|x+\frac{4}{15}\right|-\left|-3,75\right|=-\left|-2,15\right|\)
Bài 3: Thực hiện các phép tính sau bằng cách hợp lí nhất
a. \(\left(-\frac{40}{51}\cdot0,32\cdot\frac{17}{20}\right):\frac{64}{75}\)
b. \(-\frac{10}{11}\cdot\frac{8}{9}+\frac{7}{18}\cdot\frac{10}{11}\)
c. \(\frac{3}{14}:\frac{1}{28}-\frac{13}{21}:\frac{1}{28}+\frac{29}{42}-8\)
d. \(-1\frac{5}{7}\cdot15+\frac{2}{7}.\left(-15\right)+\left(-105\right).\left(\frac{2}{3}-\frac{4}{5}+\frac{1}{7}\right)\)
Bìa 4: Tính giá trị của các biểu thức sau
a. \(A=7x-2x-\frac{2}{3}y+\frac{7}{9}y\) với \(x=-\frac{1}{10};y=4,8\)
b. \(B=x+\frac{0,2-0,375+\frac{5}{11}}{-0,3+\frac{9}{16}-\frac{15}{22}}\) với\(x=-\frac{1}{3}\)
Tính các gtri các biểu thức sau :
a, A = \(\frac{2^{10}.13+2^{10}.65}{2^8.104}\)
b,B=\(^{\frac{72^3.54^2}{108^4}}\)
c,C = \(\frac{11^{22}.3^{22}.3^7-9^{15}}{\left(2.3^{14}\right)^2}\)
d, D= \(\frac{\left(3.4.2^{16}\right)}{11.2^{13}.4^{11}-16^9}\)
a, A = \(\frac{2^{10}.13+2^{10}.65}{2^8.104}\)
\(A=\frac{2^{10}\left(13+65\right)}{2^8.2^2.26}=\frac{2^{10}.78}{2^{10}.26}=\frac{78}{26}=3\)
Vậy A = 3
b, \(B=\frac{72^3.54^2}{108^4}=\frac{72^3.54^2}{\left(54.2\right)^4}=\frac{72^3.54^2}{54^4.2^4}=\frac{72^3}{54^2.2^4}=\frac{\left(8.9\right)^3}{\left(6.9\right)^2.2^4}\)
\(=\frac{\left(2^3\right)^3.9^3}{6^2.9^2.2^4}=\frac{2^9.9^3}{2^2.3^2.9^2.2^4}=\frac{2^9.9^3}{2^6.9^3}=\frac{2^9}{2^6}=2^3=8\)
Vậy B = 8
c, \(C=\frac{11.3^{22}.3^7-9^{15}}{\left(2.3^{14}\right)^2}=\frac{11.3^{29}.3^{30}}{2^2.3^{28}}=\frac{11.3^{29}.3.3^{29}}{2^2.3^{28}}=\frac{\left(11-3\right)3^{29}}{2^2.3^{28}}\)
\(=\frac{2^3.3^{29}}{2^2.3^{28}}=2.3=6\)
Vậy C = 6
d, \(D=\frac{\left(3.4.2^{16}\right)^2}{11.2^{13}.4^{11}-16^9}=\frac{\left(3.2^{18}\right)^2}{11.2^{35}-\left(2^4\right)^9}=\frac{3^2.2^{36}}{11.2^{35}-2^{36}}=\frac{3^2.2^{36}}{\left(11-2\right)2^{35}}=\frac{3^2.2}{9}=2\)
Vậy D = 2
1. Tìm x,biết:
a) \(2^x\)- 15 = 17
b) \(\left(7x-11\right)^3\)= \(2^5.5^2+200\)
c) \(^{x^{10}=1^x}\)
d) \(x^{10}=x\)
e) \(\left(2x-15\right)^5=\left(2x-15\right)^3\)
2. Tính:
\(A=\frac{11.3^{22}.3^7-9^{15}}{\left(2.3^{14}\right)^2}\)
1. Tìm x:
a) \(2^x-15=17\)
b) \(\left(7x-11\right)^3=2^5.5^2+200\)
c) \(x^{10}=1^x\)
d) \(x^{10}=x\)
e)\(\left(2x-15\right)^5=\left(2x-15\right)^3\)
2. Tính:
\(A=\dfrac{11.3^{22}.3^7-9^{15}}{\left(2.3^{14}\right)^2}\)
a) 2x - 15 = 17
2x = 25
b) ( 7x - 11 )3 = 25. 52 + 200
(7x - 11)3 = 32 . 25 + 200
(7x -11)3 = 1000
(7x-11)3 = 103
7x - 11 = 10
7x = 10+11
7x = 21
x = 21 : 7
x = 3
like nha
Thực hiện phép tính :
a)\(\frac{4}{7}-\frac{1}{14}+\left|\frac{-5}{21}\right|-\frac{-3}{7}\)
b) \(\frac{11}{15}.\frac{12}{13}-\frac{7}{15}+\frac{14}{15}.\frac{11}{13}\)
c)\(\left(\frac{3}{2}\right)^2-\left[\frac{1}{2}:2-\sqrt{81}.\left(-\frac{1}{2}\right)^2\right]\)
tính
a)\(\dfrac{-10}{11}.\dfrac{8}{9}+\dfrac{7}{18}.\dfrac{10}{11}\)
b)\(\dfrac{3}{14}:\dfrac{1}{28}-\dfrac{13}{21}:\dfrac{1}{28}+\dfrac{29}{42}:\dfrac{1}{28}-8\)
c)\(-1\dfrac{5}{7}.15+\dfrac{2}{7}\left(-15\right)+\left(-105\right).\left(\dfrac{2}{3}-\dfrac{4}{5}+\dfrac{1}{7}\right)\)
a)\(\dfrac{-10}{11}.\dfrac{8}{9}+\dfrac{7}{18}.\dfrac{10}{11}\)
=\(\dfrac{10}{11}.\dfrac{-8}{9}+\dfrac{7}{18}.\dfrac{10}{11}\)
=\(\dfrac{10}{11}(\dfrac{-8}{9}+\dfrac{7}{18})\)
=\(\dfrac{10}{11}.\dfrac{-1}{2}\)
=\(\dfrac{-5}{11}\)
b;
B = \(\dfrac{3}{14}\) : \(\dfrac{1}{28}\) - \(\dfrac{13}{21}\): \(\dfrac{1}{28}\) + \(\dfrac{29}{42}\) : \(\dfrac{1}{28}\) - 8
B = (\(\dfrac{3}{14}\) - \(\dfrac{13}{21}\) + \(\dfrac{29}{42}\)) - 8
B = (\(\dfrac{9}{42}\) - \(\dfrac{26}{42}\) + \(\dfrac{29}{42}\)) - 8
B = (\(\dfrac{-17}{42}\) + \(\dfrac{29}{42}\)) - 8
B = \(\dfrac{2}{7}\) - 8
B = \(\dfrac{2}{7}-\dfrac{56}{7}\)
B = - \(\dfrac{54}{7}\)
c; C = -1\(\dfrac{5}{7}\).15 + \(\dfrac{2}{7}\)(-15) + (-105).(\(\dfrac{2}{3}\) - \(\dfrac{4}{5}\) + \(\dfrac{1}{7}\))
C = - 15.(- 1 - \(\dfrac{5}{7}\) + \(\dfrac{2}{7}\) + \(\dfrac{14}{3}\) - \(\dfrac{28}{5}\) + \(1\))
C = -15.[(1 - 1) - (\(\dfrac{5}{7}\) - \(\dfrac{2}{7}\)) + \(\dfrac{14}{3}\) - \(\dfrac{28}{5}\)]
C = -15.[0 - \(\dfrac{3}{7}\) + \(\dfrac{14}{3}\) - \(\dfrac{28}{5}\)]
C = -15 . [- \(\dfrac{45}{105}\) + \(\dfrac{490}{105}\) - \(\dfrac{588}{105}\)]
C = -15. [ \(\dfrac{445}{105}\) - \(\dfrac{588}{105}\)]
C = - 15.(- \(\dfrac{143}{105}\))
C = \(\dfrac{143}{7}\)
Tính :
a) \(5+\left(-7\right)+9+\left(-11\right)+13+\left(-15\right)\)
b) \(\left(-6\right)+8+\left(-10\right)+12+\left(-14\right)+16\)
a)
\(5+\left(-7\right)+9+\left(-11\right)+13+\left(-15\right)\)
\(=\left[5+\left(-7\right)\right]+\left[9+\left(-11\right)\right]+\left[13+\left(-15\right)\right]\)
\(=\left(-2\right)+\left(-2\right)+\left(-2\right)=-6\)
b)
\(\left(-6\right)+8+\left(-10\right)+12+\left(-14\right)+16\)
\(=\left[\left(-6\right)+8\right]+\left[\left(-10\right)+12\right]+\left[\left(-14\right)+16\right]\)
\(=2+2+2=6\)
Tìm giá trị nhỏ nhất của :
a) A = \(21\cdot\left|4x+6\right|+\frac{33}{3\left|4x+6\right|+5}\)b) B = \(\frac{6\left|y+5\right|+14}{2\left|y+5\right|+14}\)c) C = \(\frac{-15\left|x+7\right|-68}{3\left|x+7\right|+12}\)