a)
\(x^2-6x+9-x^2-2x=1\)
\(-8x+9=1\)
\(-8x=-8\)
x=1
b)
\(\left(3x+2-2x+5\right)\left(3x+2+2x-5\right)=0\)
\(\left(x+7\right)\left(5x-3\right)=0\)
x+7 = 0 hoặc 5x-3=0
x=-7      hoặc 5x=3
x=-7      hoặc   x=3/5

a)
\(\dfrac{x}{2}=\dfrac{y}{3}=\dfrac{z}{4}=\dfrac{x+y+z}{2+3+4}=\dfrac{180}{9}=20\)
x=40⁰
y=60 độ
z=80 độ
vậy ..........



 

bài 2
=2:(-1/6)³=2:\(\dfrac{-1}{216}=-432\)

bài 1
trường hợp 1
-x=\(1\dfrac{2}{3}\)
=>x=-5/3
TH2
x=5/3
bài 3
\(\left|x+\dfrac{5}{3}\right|-\dfrac{2}{6}=0\)
=>\(\left|x+\dfrac{5}{3}\right|=\dfrac{2}{6}\)
trường hợp 1
x+5/3=2/6
x=-4/3
TH2
-x-5/3=2/6
-x=2
x=-2

A= (100x44+50x64)x(37414,8:1000+2242,52:100)
A = 100x(44+32)x(3741,48+2242,52) : 100
=(44+32)x(3741,48+2242,52)
=76x5984=454784
B= (16x14,96x25)x(27x38+19x146)
= 5984x6x(171+379)
=5984x550=3291200

b)
\(=5\sqrt{3}+4\sqrt{3}-10\sqrt{3}=-\sqrt{3}\)

a)
\(=\sqrt{a^3}.\sqrt{\left(a-1\right)^2}=\sqrt{a^3}.\left(a-1\right)\) với a >_1
b)
\(=5\sqrt{3}+3\sqrt{5}-10\sqrt{3}=3\sqrt{5}-5\sqrt{3}\)
c)
\(=7\sqrt{2}-6\sqrt{2}+\sqrt{2}=2\sqrt{2}\)
d)\(=-5\sqrt{3a}+27\) \(\left(a\ge0\right)\)
e)
\(=3\sqrt{2a}-10\sqrt{2a}+21\sqrt{2a}+28 \left(a\ge0\right)\)
\(=14\sqrt{2a}+28\)

\(=\left(2u-4v\right)^3\)

\(=\left(\dfrac{2}{3}a\right)^3-3.\left(\dfrac{2}{3}\right)^2a^2.2b+3.\dfrac{2}{3}a.4b^2-\left(2b\right)^3=\left(\dfrac{2}{3}a-2b\right)^3\)

\(\left(\sqrt{2}x-y\right)^2=2x^2-2\sqrt{2}xy+y^2\)