Question

Tìm số nguyên x biết

a)   2x + 12 = 3( x- 7 )

b)   | -9 - x | - 5 = 12

Answer 1

\(a,2x+12=3\left(x-7\right)\)

\(2x+12=3x-21\)

\(2x-3x=-21-12\)

\(-x=-33\)

\(x=33\)

\(b,\left|-9-x\right|-5=12\)

\(\left|-9-x\right|=17\)

\(\Rightarrow\orbr{\begin{cases}-9-x=17\\-9-x=-17\end{cases}\Rightarrow\orbr{\begin{cases}x=-26\\x=8\end{cases}}}\)

Answer 2

\(\text{a) 2x + 12 = 3(x-7)}\)

\(\Rightarrow2x+12=3x-3.7\)

\(\Rightarrow2x+12=3x-21\)

\(\Rightarrow2x+12+21=3x\)

\(\Rightarrow2x+33=3x\)

\(\Rightarrow3x-2x=33\)

\(\Rightarrow x\left(3-2\right)=33\)

\(\Rightarrow x=33\left(tm\right)\)

Vậy x =33

Answer 3

a) 2x+12=3(x-7)

2x+12=3x-21

2x-3x=-12-21

-x=-33

x=33

Vậy x=33

b) |-9-x|-5=12

|-9-x|=12+5

|-9-x|=17

\(\Rightarrow\orbr{\begin{cases}-9-x=-17\\-9-x=17\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=8\\x=-26\end{cases}}\)

Vậy x\(\in\){8;-26}

Answer 4

a)   2x + 12 = 3( x- 7 )

2x +12 = 3x -21

2x+12-3x = -21

-x +12 = -21

-x= -21 -12

-x = -33

=> x= 33

Vậy...

b)   | -9 - x | - 5 = 12

| -9 -x | = 12+5

|-9 -x|= 17

TH1: -9-x = 17

x= -9 - 17

x= -26

TH2: -9 -x = -17

x= -9 - (-17)

x= 8

Vậy...

Answer 5

\(\text{b) |}-9-x|-5=12\)

\(\Rightarrow|-9-x|=12+5\)

\(\Rightarrow|-9-x|=17\)

\(\Rightarrow\orbr{\begin{cases}-9-x=17\\-9-x=-17\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=-9-17\\x=-9-\left(-17\right)\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=-26\\x=-9+17\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=-26\\x=8\end{cases}}\)(tm)

Vậy x \(\in\){-26;8}

Answer 6

a) \(2x+12=3\left(x-7\right)\)
\(\Rightarrow2x+12=3x-21\)

\(\Rightarrow2x-3x=-21-12\)
\(\Rightarrow-x=-33\)

\(\Rightarrow x=33\)

b)\(\left|-9-x\right|-5=12\)

\(\Rightarrow\left|-9-x\right|=17\)

\(\Leftrightarrow\orbr{\begin{cases}-9-x=17\\-9-x=-17\end{cases}}\Leftrightarrow\orbr{\begin{cases}-x=-9-17\\-x=-9+17\end{cases}\Leftrightarrow\orbr{\begin{cases}-x=-26\\-x=8\end{cases}}}\Leftrightarrow\orbr{\begin{cases}x=26\\x=8\end{cases}}\)

Vậy ...

HỌC TỐT

Answer 7

Mik nhầm phần b nha bn chỗ \(\orbr{\begin{cases}-x=-26\\-x=8\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=26\\x=-8\end{cases}}\)phải như này nha bn

HỌC TỐT NHA

Answer 8

Cảm ơn ạ

Answer 9

Trả lời:

\(a)\)\(2x+12=3\left(x-7\right)\)

\(\Leftrightarrow2x+12=3x-21\)

\(\Leftrightarrow x=33\)

Vậy\(x=33\)

\(b)\)\(\left|-9-x\right|-5=12\)

\(\Leftrightarrow\left|-9-x\right|=17\)

\(\Leftrightarrow\orbr{\begin{cases}-9-x=17\\-9-x=-17\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=-26\\x=8\end{cases}}\)

Vậy\(x=-26\)hoặc\(x=8\)

Hok tốt!

Good girl

Answer 10

\(a,\)\(2x+12=3\left(x-7\right)\)

       \(2x+12=3x-21\)

        \(12+21=3x-2x\)

               \(33=x\)

Vậy x = 33

\(b,|-9-x|-5=12\)

    \(|-9-x|=17\)

\(\Rightarrow\orbr{\begin{cases}-9-x=17\\-9-x=-17\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}x=-26\\x=8\end{cases}}\)

Answer 11

\(a)2x+12=3\left(x-7\right)\)

\(\Rightarrow2x+12=3x-21\)

\(\Rightarrow2x-3x=\left(-21\right)-12\)

\(\Rightarrow-x=-33\)

\(\Rightarrow x=33\)

Vậy \(x=33\)

\(b)\left|-9-x\right|-5=12\)

\(\Rightarrow\left|-9-x\right|=12+5\)

\(\Rightarrow\left|-9-x\right|=17\)

\(\Rightarrow\orbr{\begin{cases}-9-x=17\\-9-x=-17\end{cases}\Rightarrow\orbr{\begin{cases}x=-26\\x=8\end{cases}}}\)

Vậy \(x\in\left\{-26;8\right\}\)

#Mạt Mạt#

Answer 12

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