Question

Tĩm x

a,(111-x )+7mũ 2=149

b , | x| + 18 = 163+(-45)

c, 7 mũ x-4 x6 =2058

Answer 1

\(a)\)\(\left(111-x\right)+7^2=149\)

\(\Leftrightarrow\)\(\left(111-x\right)+49=149\)

\(\Leftrightarrow\)\(\left(111-x\right)=149-49\)

\(\Leftrightarrow\)\(111-x=100\)

\(\Leftrightarrow\)\(x=111-100\)

\(\Leftrightarrow\)\(x=11\)

Answer 2

\(b)\)\(\left|x\right|+18=163+\left(-45\right)\)

\(\Leftrightarrow\)\(\left|x\right|+18=163-45\)

\(\Leftrightarrow\)\(\left|x\right|+18=118\)

\(\Leftrightarrow\)\(\left|x\right|=118-18\)

\(\Leftrightarrow\)\(\left|x\right|=100\)

\(\Leftrightarrow\)\(x=100\)

Answer 3

\(c)\)\(7^{x-4}\times6=2058\)

\(\Leftrightarrow\)\(7^{x-4}=2058\div6\)

\(\Leftrightarrow\)\(7^{x-4}=343\)

\(\Leftrightarrow\)\(7^{x-4}=7^3\)

\(\Leftrightarrow\)\(x-4=3\)

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

\(\Leftrightarrow\)\(x=7\)

Answer 4

|x|=100 do đó x=-100 và 100

Answer 5

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