Tìm số nguyên x,biết:
a)-6x=18
b)35-3.|x|=5.(2 mũ 3 – 4)
c)10+2.|x|=2.(3 mũ 2 – 1)
Tìm số nguyên x,biết: a)-6x=18 b)35-3.|x|=5.(2 mũ 3 – 4) c)10+2.|x|=2.(3 mũ 2 – 1)
By Savannah
By Savannah
Tìm số nguyên x,biết:
a)-6x=18
b)35-3.|x|=5.(2 mũ 3 – 4)
c)10+2.|x|=2.(3 mũ 2 – 1)
a,-6x=18
x=18:(-6)
x=-3
b,35-3.IxI=5.(2^3-4)
35-3.IxI=5.4
35-3.IxI=20
3.IxI=15
3.x=15 hoặc 3.x=-15
x=15:3 x=-15:3
x=5 x=-5
c)10+2.|x|=2.(3^ 2 – 1)
10+2.IxI=2.8
10+2.IxI=16
2.IxI=6
2.x=6 hoặc 2.x=-6
x=6:2 x=-6:2
x=3 x=-3
`a)-6x=18`
`→x=18:(-6)`
`→x=-3`
Vậy `x=-3`
`b)35-3|x|=5(2^3-4)`
`→35-3|x|=5.4`
`→35-3|x|=20`
`→3|x|=35-20`
`→3|x|=15`
`→|x|=15:3`
`→|x|=5`
`→` \(\left[ \begin{array}{l}x=5\\x=-5\end{array} \right.\)
Vậy `x∈{5;-5}`
`c)10+2|x|=2(3^2-1)`
`→10+2|x|=2.8`
`→10+2|x|=16`
`→2|x|=16-10`
`→2|x|=6`
`→|x|=6:2`
`→|x|=3`
`→` \(\left[ \begin{array}{l}x=3\\x=-3\end{array} \right.\)
Vậy `x∈{3;-3}`