b6 fashion - long hours - contacted  - clients - grades 

b5 c làm ở dưới r í

Bài 4 nào bài 8 đâu em 

là sao

Bài 6:

Áp dụng tính chất của dãy tỉ số bằng nhau, ta được:

\(\dfrac{a}{41}=\dfrac{b}{29}=\dfrac{c}{30}=\dfrac{a+b}{41+29}=\dfrac{700}{70}=10\)

Do đó: a=410; b=290; c=300

dạ ko ạ, làm dạng 1 và 2 ạ

???

Bài nào :>

lỗi r

\(\sqrt{9x+9}-2\sqrt{\dfrac{x+1}{4}}=4\left(đk:x\ge-1\right)\)

\(\Leftrightarrow3\sqrt{x+1}-\sqrt{x+1}=4\)

\(\Leftrightarrow2\sqrt{x+1}=4\)

\(\Leftrightarrow\sqrt{x+1}=2\Leftrightarrow x+1=4\Leftrightarrow x=3\left(tm\right)\)

Bài 2:

e) \(\sqrt{4x-8}-12\sqrt{\dfrac{x-2}{9}}=\sqrt{x-2}-12\left(đk:x\ge2\right)\)

\(\Leftrightarrow\sqrt{4}.\sqrt{x-2}-12.\sqrt{\dfrac{1}{9}}.\sqrt{x-2}=\sqrt{x-2}-12\)

\(\Leftrightarrow2\sqrt{x-2}-4\sqrt{x-2}=\sqrt{x-2}-12\)

\(\Leftrightarrow3\sqrt{x-2}=12\)

\(\Leftrightarrow\sqrt{x-2}=4\)

\(\Leftrightarrow x-2=16\Leftrightarrow x=18\left(tm\right)\)

d) \(\sqrt{9x+9}-2\sqrt{\dfrac{x+1}{4}}=4\left(đk:x\ge-1\right)\)

\(\Leftrightarrow\sqrt{9}.\sqrt{x+1}-2.\sqrt{\dfrac{1}{4}}.\sqrt{x+1}=4\)

\(\Leftrightarrow3\sqrt{x+1}-\sqrt{x+1}=4\)

\(\Leftrightarrow2\sqrt{x+1}=4\Leftrightarrow\sqrt{x+1}=2\)

\(\Leftrightarrow x+1=4\Leftrightarrow x=3\)

Bài 2:

e) \(\sqrt{4x-8}-12.\sqrt{\dfrac{x-2}{9}}=\sqrt{x-2}-12\Rightarrow\sqrt{4}.\sqrt{x-2}-12.\sqrt{\dfrac{1}{9}}.\sqrt{x-2}=\sqrt{x-2}-12\Rightarrow2\sqrt{x-2}-4.\sqrt{x-2}=\sqrt{x-2}-12\Rightarrow3.\sqrt{x-2}=12\Rightarrow\sqrt{x-2}=4\Rightarrow x-2=16\Rightarrow x=18\left(tm\right)\)

Bài 12: 

a: Xét ΔABM và ΔACN có

AB=AC

\(\widehat{ABM}=\widehat{ACN}\)

BM=CN

Do đó: ΔABM=ΔACN

bài 3.

1.\(\dfrac{-51}{136}=\dfrac{-3}{8};\dfrac{-60}{108}=\dfrac{-5}{9};\dfrac{26}{-156}=\dfrac{-1}{6}\)

\(\dfrac{-3}{8}=\dfrac{-24}{72};\dfrac{-5}{9}=\dfrac{-40}{72};\dfrac{-1}{6}=\dfrac{-12}{72}\)

2.\(\dfrac{-165}{270}=\dfrac{-11}{18};\dfrac{-91}{-156}=\dfrac{7}{12};\dfrac{-210}{1134}=\dfrac{-5}{27}\)

\(\dfrac{-11}{18}=\dfrac{-66}{108};\dfrac{7}{12}=\dfrac{63}{108};\dfrac{-5}{27}=\dfrac{-20}{108}\)

1. -51/136=-3/8; -60/108=-5/9;26/-156=-1/6

-3/8=-24/71;-5/9=-40/72;-1/6=-12/72