Đáp án:
Giải thích các bước giải:
k) ]x – 10] – (-12) = 4
x-10 +12 = 4
x= 4-12+10
x= 2
I) ]x + 2] < 3
x+2-2< 3-2
x < 1
m) – 12(x – 5) + 7(3 – x) = 15
-12x + 60 + 21 -7x =15
-12x-7x = 15 -21-60
-19x = -66
x= 66 / 19
n) x.(x + 3) = 0
=> \(\left[ \begin{array}{l}x=0\\x+3=0\end{array} \right.\)
=> \(\left[ \begin{array}{l}x=0\\x=-3\end{array} \right.\)
o) (x – 2).(5 – x) = 0
\(\left[ \begin{array}{l}x-2=0\\5-x=0\end{array} \right.\)
=> \(\left[ \begin{array}{l}x=2\\x=5\end{array} \right.\)
p) (3x + 6). (x² – 9) = 0
=> \(\left[ \begin{array}{l}3x+6=0\\x^2-9=0\end{array} \right.\)
=> \(\left[ \begin{array}{l}3x=-6\\x^2=9\end{array} \right.\)
=> \(\left[ \begin{array}{l}x=-2\\x= -3 hoặc x=3\end{array} \right.\)
