Đáp án:
Giải thích các bước giải:
bài 9
a)|10x+7|<37
⇒\(\left[ \begin{array}{l}10x+7<37\\10x+7<-37\end{array} \right.\)
⇒\(\left[ \begin{array}{l}10x<30\\10<-44\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x<3\\x<-4,4\end{array} \right.\)
vậy x<3,x<-4,4
b)|3-8x|≤19
⇒\(\left[ \begin{array}{l}3-8x≤ 19\\3-8x≤ -19\end{array} \right.\)
⇒\(\left[ \begin{array}{l}8x≤-16\\8x≤22\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x≤-2\\x≤2,75\end{array} \right.\)
vậy x≤-2,x≤2,75
c)║x-4║>3
⇒\(\left[ \begin{array}{l}x-4>3\\x-4>-3\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x>7\\x>1\end{array} \right.\)
vậy x>7;x>1
bài 10:
a)x-$1^{3}$ =27
⇒x-1=27
⇒x=28
vậy x=28
b)$x^{2}$ +x=0
⇒x(x+1)=0
⇒\(\left[ \begin{array}{l}x=0\\x+1=0\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x=0\\x=-1\end{array} \right.\)
vậy x∈{0;1}
b)2x+$1^{2}$ =25
⇒2x+1=25
⇒2x=24
⇒x=12
vậy x=12
xin hay nhât nha
