7 phần √3 - √2 - √147 - 2√18
Tính nhanh :
1) 18× 76 + 24 × 18 -150
2) 147+230 +53 + 70
3) 7 × 85 + 27 × 7 - 7 ×12
a,18 . 76 + 24 . 18 - 150 = 18 . ( 76 + 24 ) - 150= 18 . 100 - 150 = 1800 - 150=1650
b, 147 + 230 + 53 + 70 = ( 147 + 53 ) + ( 230 + 70) = 200 + 300=500
c, 7 . 85 + 27 . 7 - 7 . 12=(85 + 27 -12 ) . 7=100 . 7=700
Dấu . là phép nhân
1) 18 . 76 + 24 . 18 -150
= 18( 76 + 24 ) - 150
= 18 . 100 -150
= 1800 - 150
= 1650
2) 147+230 +53 + 70
= ( 147 + 53 ) + ( 230 + 70 )
= 200 + 200
= 400
3) 7 × 85 + 27 × 7 - 7 ×12
= 7( 85 + 27 - 12 )
= 7 . 100
= 700
Tính giá trị
\(\frac{7}{\sqrt{3}-\sqrt{2}}-\sqrt{147}-2\sqrt{18}\)
\(=\frac{7}{\sqrt{3}-\sqrt{2}}-7\sqrt{3}-6\sqrt{2}=\frac{7-\left(7\sqrt{3}+6\sqrt{2}\right)\left(\sqrt{3}-\sqrt{2}\right)}{\sqrt{3}-\sqrt{2}}\)
\(=\frac{7-21+7\sqrt{6}-6\sqrt{6}+12}{\sqrt{3}-\sqrt{2}}=\frac{-2+\sqrt{6}}{\sqrt{3}-\sqrt{2}}=\frac{\sqrt{2}\left(\sqrt{3}-\sqrt{2}\right)}{\sqrt{3}-\sqrt{2}}=\sqrt{2}\)
1 . Tính
3^11 : 3^9 - 147 : 7^2
7^18 : 7^16 + 2^3 . 3^3
11^25 : 11^23 - 3^5 : ( 1^10 + 2^3 ) - 60
2 . Cho S = 3^1 + 3^2 + 3^3 + 3^4 + ... + 3^2015 . Tính S
2S=32+33+34+....+32016
2S-S=(32+33+34+...+32016)-(3+32+33+....+32015)
S=22016-3
B1:Tính
a,\(\sqrt{\left(4-\sqrt{17}\right)^2}-\left(\sqrt{17}+2\right)\) b,\(\dfrac{7}{\sqrt{3}-\sqrt{2}}-\sqrt{147}-2\sqrt{18}\)
c,\(\dfrac{6}{\sqrt{5}-2}-\dfrac{6}{\sqrt{5}+2}+\sqrt{8}-4\sqrt{\dfrac{1}{7}}\) ; \(\left(\dfrac{1}{2}\sqrt{\dfrac{1}{2}}-\dfrac{3}{2}\sqrt{2}+\dfrac{4}{5}\sqrt{200}\right):\dfrac{1}{8}\)
\(a,=\sqrt{17}-4-\sqrt{17}-2=-6\\ b,=7\left(\sqrt{3}+\sqrt{2}\right)-7\sqrt{3}-6\sqrt{2}\\ =7\sqrt{3}+7\sqrt{2}-7\sqrt{3}-6\sqrt{2}=\sqrt{2}\\ c,=\dfrac{6\sqrt{5}+12-6\sqrt{5}+12}{3}+2\sqrt{2}-\dfrac{4\sqrt{7}}{7}\\ =8+2\sqrt{2}-\dfrac{4\sqrt{7}}{7}=\dfrac{56+14\sqrt{2}-4\sqrt{7}}{7}\\ d,=\left(\dfrac{\sqrt{2}}{4}-\dfrac{6\sqrt{2}}{4}+8\sqrt{2}\right):\dfrac{1}{8}=\dfrac{-5\sqrt{2}+32\sqrt{2}}{4}\cdot8=54\sqrt{2}\)
Tinh nhanh
a ) 18*76+24*18-150
b ) 147 +230+53+70
c) 7*85+27*7-7*12
d) 58*75+58*50-58*25
e) 2 va3/5-2/5*(5/8-7/12)
f ) 1/3-5/4*4/15
D=√147 +√54 -4√27
A =√112 - 7√(1/7) - 14√(1/28)-21/√7
B = 3√2(4 -√2) + 3(1 - 2√2)^2
C = 2√27 + 5√12 - 3√48
E = (√15 - 2√3)^2 + 12√5
F = 3√50 - 7√8 + 12√18
G = 2√80 - 2√245 + 2√180
H =√28 - 4√63 + 7√112
I =√44 -√176 + 2√275
cái này bấm máy tính là thầy mình k cho đâu =))) phải trình bày ra mà
D=√147 +√54 -4√27
A =√112 - 7√(1/7) - 14√(1/28)-21/√7
B = 3√2(4 -√2) + 3(1 - 2√2)^2
C = 2√27 + 5√12 - 3√48
E = (√15 - 2√3)^2 + 12√5
F = 3√50 - 7√8 + 12√18
G = 2√80 - 2√245 + 2√180
H =√28 - 4√63 + 7√112
I =√44 -√176 + 2√275
Tìm số nguyên x biết:
a) 6 phần 5 = 18 phần x
b) 3 phần 4 = -21 phần x
c) 2 phần -7 = 18 phần x
d) -5 phần 2 = 10 phần âm x
\(a,\dfrac{6}{5}=\dfrac{18}{x}\\ \Rightarrow x=18:\dfrac{6}{5}\\ \Rightarrow x=15\\ b,\dfrac{3}{4}=\dfrac{-21}{x}\\ \Rightarrow x=-21:\dfrac{3}{4}\\ \Rightarrow x=-28\\ c,\dfrac{2}{-7}=\dfrac{18}{x}\\ \Rightarrow x=18:\dfrac{2}{-7}\\ \Rightarrow x=-63\\ d,\dfrac{-5}{2}=\dfrac{10}{-x}\\ \Rightarrow x=-10:\dfrac{-5}{2}\\ \Rightarrow x=4\)
\(a,\dfrac{6}{5}=\dfrac{18}{x}\Rightarrow6.x=5.18=90\\ \Rightarrow6.x=90\\ \Rightarrow x=15\\ b,\dfrac{3}{4}=\dfrac{-21}{x}\Rightarrow3.x=4.21=84\\ \Rightarrow x=28\)
\(a,\dfrac{6}{5}=\dfrac{18}{x}=>x=\dfrac{18.5}{6}=\dfrac{90}{6}=15\)
\(b,\dfrac{3}{4}=-\dfrac{21}{x}=>x=-\dfrac{21.4}{3}=-\dfrac{84}{3}=24\)
\(c,\dfrac{2}{-7}=\dfrac{18}{x}=>x=\dfrac{18.-7}{2}=-\dfrac{126}{2}=-63\)
\(d,-\dfrac{5}{2}=\dfrac{10}{-x}=>-x=\dfrac{10.2}{-5}=\dfrac{20}{-5}=-4=>x=4\)
1) Tinh nhanh:
a) 18*76+24*18-150
b) 147+230+53+70
c) 7*85+27*7-7*12
d) 58*75+58*50-58*25
e)2va3/5-2/5*(5/8-7/12)
f) 1/3-5/4*4/15