- M.n giúp mih giải môn Hóa với ạ. Mih đang cần gấp T.T
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a: Xét hình thang ABCD có MN//AB//CD
nên AM/AD=BN/BC
b: MA/AD+NC/BC
=BN/BC+NC/BC
=1
a)
\(\sqrt{9+4\sqrt{5}}\cdot\sqrt{6-2\sqrt{5}}\\ =\sqrt{4+4\sqrt{5}+5}\cdot\sqrt{1-2\sqrt{5}+5}\\ =\sqrt{\left(2+\sqrt{5}\right)^2}\cdot\sqrt{\left(1-\sqrt{5}\right)^2}\\ =\left(2+\sqrt{5}\right)\left(1-\sqrt{5}\right)\)
b)
\(\sqrt{3+2\sqrt{2}}-\sqrt{6-4\sqrt{2}}\\ =\sqrt{2+2\sqrt{2}+1}-\sqrt{4-4\sqrt{2}+2}\\ =\sqrt{\left(\sqrt{2}+1\right)^2}-\sqrt{\left(2-\sqrt{2}\right)^2}\\ =\sqrt{2}+1-2+\sqrt{2}=2\sqrt{2}-1\)
a: =>31-x-39=-58
=>-8-x=-58
=>x+8=58
hay x=50
b: =>-129-35+x=55
=>x-164=55
hay x=219
c: =>|x-7|=-37+127=90
=>x-7=90 hoặc x-7=-90
=>x=97 hoặc x=-83
d: =>|x-14|<2
=>x-14>-2 và x-14<2
=>12<x<16
e: =>315-x-315=43-12
=>-x=31
hay x=-31
f: =>|x-4|=4
=>x-4=4 hoặc x-4=-4
=>x=8 hoặc x=0
a: =>25-25+x=12+42-65
=>x=-11
b: =>|x+3|=4
=>x+3=4 hoặc x+3=-4
=>x=1 hoặc x=-7
c: =>x+17=13
hay x=-4
d: =>x+25-x=13-x
=>13-x=25
hay x=-12
e: =>15-30-x=x-(27-8)
=>-15-x=x-19
=>-x-x=-19+15
=>-2x=-4
hay x=2
f: \(\Leftrightarrow\left(12x-64\right)=4\cdot8=32\)
=>12x=96
hay x=8
\(g,\left[119-\left(3^3-10\right)\right].x=2448\\ \Leftrightarrow\left[119-\left(27-10\right)\right].x=2448\\ \Leftrightarrow\left[119-27+10\right].x=2448\\ \Leftrightarrow102.x=2448\\ \Leftrightarrow x=\dfrac{2448}{102}=24\\ h,\left[\left(10-x\right).2+51\right]:3-2=3\\ \Leftrightarrow\left[\left(10-x\right).2+51\right]:3=3+2=5\\ \Leftrightarrow\left[\left(10-x\right).2+51\right]=5.3=15\\ \Leftrightarrow\left(10-x\right).2=15-51=-36\\ \Leftrightarrow10-x=\dfrac{-36}{2}=-18\\ \Leftrightarrow x=10-\left(-18\right)=28\\ i,\left(x-12\right)-15=20-\left(17+x\right)\\ \Leftrightarrow x-12-15=20-17-x\\ \Leftrightarrow x+x=20-17+12+15\\ \Leftrightarrow2x=30\\ \Leftrightarrow x=\dfrac{30}{2}=15\)
\(k,-12-\left|13-x\right|=-21\\ \Leftrightarrow\left|13-x\right|=-12-\left(-21\right)=-12+21=9\\ \Leftrightarrow\left[{}\begin{matrix}13-x=9\\13-x=-9\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=13-9=4\\x=13-\left(-9\right)=13+9=22\end{matrix}\right.\)
e: =(2004-2004)+(54-54)+(-15)=-15
f: =(-45789x2)-(357-57)=-91578-300=-91878
g: =(1259+1259)-(1409-1409)-12=2506
h: =(2750x2)-1229+438+29+438
=5500-1200+876
=5176
i: =-5+(-37+37)+(151+151)-45
=-50+302
=252
k: =(53-53)+(-145+145)-(359+259)=-618
e)2004-15+54-2004-54=(2004-2004)+(54-54)-15=-15
f)-45789-357-45789+57=(-45789-45789)-(357-57)=-91578-300=-91878
g)1259-1409-12+1259+140=(1259+1259)+(-1409+1409)-12=2518-12=2506
h)2750-1229+2750-(-438-29-438)=(2750+2750)-1229+438+29+438=5500-(1229-29)+(438+438)=5500-1200+876=5176
i)-5+-37-45+151--37=-5-37-45+151+37=(-5-45)+(-37+37)+151=-50+151=101
k)53-145-359-53+145-259=(53-53)+(-145+145)+(-359-259)=-618
l)-81-132-547+181-132-53=(-81+181)-(547+53)-(132+132)=100-600-264=-764
m)50-2016+50-118+2016-18=(50+50)+(-2016+2016)-(118+18)=100-136=-36
bài gì thế bn
Mih có đăng lên r đó !