) Tìm số nguyên x, biết:
a) x + 5 = 2015 – (12 – 7) b) |x-5| = 11
c) 2^(x -1) = 8
) Tìm số nguyên x, biết: a) x + 5 = 2015 – (12 – 7) b) |x-5| = 11 c) 2^(x -1) = 8
By Eden
By Eden
) Tìm số nguyên x, biết:
a) x + 5 = 2015 – (12 – 7) b) |x-5| = 11
c) 2^(x -1) = 8
`a)x + 5 = 2015 – (12 – 7)`
`x + 5 = 2015 – 5`
`x = 2010 – 5 `
`x = 2005`
b)Từ `|x-5| = 11`
`=> x-5=11` hoặc `x-5=-11`
`=> x=16` hoặc `x=-6 `
`c)2^(x -1) = 8`
`2^(x -1) = 2^3`
`x – 1 = 3`
`x = 3 + 1`
`x = 4`
a) x + 5 = 2015 – (12 – 7)
x +5 =2015-5
x + 5 =2010
x =2010-5
x =2005
b) |x-5| = 11
⇔\(\left[ \begin{array}{1}x=11\\x=-11\end{array} \right.\)
TH1:x-5=11
x =11+5
x =16
TH2:x-5=-11
x =-11+5
x =-6
c)2^(x -1) = 8
2^(x -1) = 2^3
x–1=3x–1=3
`x = 3 + 1
x=4