a) \(\dfrac{x}{2}=-\dfrac{6}{3}=-2\Rightarrow x=2.\left(-2\right)=-4\)

b) \(\dfrac{2}{x}=\dfrac{y}{-3}\Leftrightarrow y=-\dfrac{6}{x}\) y thuộc Z => x thuộc {+-6;+-3;+-2;+-1}

(x;y) =(-6;1);(-3;2); (-2;3);(-1;6) ; (6;-1);(3-2);(2;-3);(1;-6)

\(\)1)A={xEN*/x\(\ge\)6}

2) a)\(\Rightarrow\left(x+15\right).9=45\)

   \(\Rightarrow x+15=45:9=5\)

   \(\Rightarrow x=5-15\)

   \(\Rightarrow x=-10\)

b) \(\Rightarrow10+2x=20\)

   \(\Rightarrow2x=20-10=10\)

   \(\Rightarrow x=10:2=5\)

tíc mình nha

bai 1a ban viet duoi dang liet ke nha ! cam on nhieu! 

GIUP MINH VOI

a) \(3\left(x-4\right)-\left(8-x\right)=12\)

\(3x-12-8+x=12\)

\(4x=12+12+8\)

\(4x=32\)

\(x=8\)

b) \(4\left(x-5\right)-\left(x-7\right)=-19\)

\(4x-20-x+7=-19\)

\(3x=-19+20-7\)

\(3x=-6\)

\(x=-2\)

c) \(7\left(x-3\right)-5\left(3-x\right)=11x-5\)

\(7\left(x-3\right)+5\left(x-3\right)=11x-5\)

\(\left(x-3\right).12=11x-5\)

\(12x-36-11x+5=0\)

\(x-31=0\)

\(x=31\)

a. c1:15x12-3x3x10 = 180-150=30

c2: 15x12-15x10 = 15x(12-10) = 15x2 = 30

b. c1: 45-9x18=45-162=-117

c2: 45-9x13-9x5=45-45-9x13=-117

c. c1: 29x6-19x16=174-304=-130

c2: 29x19-29x13-19x29+19x13=13x(19-29)=13x(-10)=-130

a. 

Cách 1: 

15.12 - 3.5.10

= 180 - 150

= 30

Cách 2:

15.12 - 3.5.10

= 15 .12 - 15.10

= 15. ( 12 -10)

= 15.2

= 30 

Tiếp tương tự. Chúc bạn học tốt!!

\(x\ge2\)  \(\Rightarrow\)      \(x-2\ge0\)

\(\Rightarrow\)\(\left|x-2\right|=x-2\)

Ta có:         \(3\left|x-2\right|+2x=19\)

\(\Leftrightarrow\)\(3\left(x-2\right)+2x=19\)

\(\Leftrightarrow\)\(3x-6+2x=19\)

\(\Leftrightarrow\)\(5x=25\)

\(\Leftrightarrow\)\(x=5\)

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