Làm hộ mk bài 1-2 số nha( cùng 1 tờ)
tick cho mk nha:
Bài 1: 1) \(-3,28-4,52+12,4=\frac{23}{5}\) hay 4,6.
2) \(-1,27-3,33+6,05\times2=\frac{15}{2}\) hay 7,5.
3) \(\frac{2,36-1,4+2,17\times2}{1,24+2,26}=\frac{53}{35}\)
4) \(\frac{2,4\times\left(-6\right)+5,3\times4}{4,2\times2,25-3,4\times1,5}=\frac{136}{87}\)
Bài 2:\(\left|2x+1\right|=5\)
\(\Rightarrow\) \(2x+1=\pm5\)
* \(2x+1=5\)
2x = 4 \(\Rightarrow x=2\)
* 2x + 1=\(-5\)
2x = \(-6\) \(\Rightarrow\) x= \(-3\)
Vậy \(\left[\begin{array}{nghiempt}2\\-3\end{array}\right.\)
b) \(\left|3x+5\right|=\left|\frac{-7}{3}\right|\)
\(\left|3x+5\right|=\frac{7}{3}\)
\(3x+5=\pm\frac{7}{3}\)
* 3x + 5 =\(\frac{7}{3}\)
3x = \(\frac{-8}{3}\) \(\Rightarrow x=\frac{-8}{9}\)
* 3x + 5 = \(\frac{-7}{3}\)
3x = \(\frac{-22}{3}\)
x = \(\frac{-22}{9}\)
Vậy \(\left[\begin{array}{nghiempt}\frac{-8}{9}\\\frac{-22}{9}\end{array}\right.\)
c) \(\left|3x+1\right|=\left|4-x\right|\)
\(\Rightarrow\left[\begin{array}{nghiempt}3x-1=4-x\left(1\right)\\3x-1=-4+x\left(2\right)\end{array}\right.\)
(1) \(\Leftrightarrow\) 3x +1= 4 \(-x\)
3x + x = 4\(-1\)
4x = 3 \(\Rightarrow x=\frac{3}{4}\)
(2) \(\Leftrightarrow\) 3x +1 = \(-4+x\)
3x \(-x\) = \(-4-1\)
2x = \(-5\) \(\Rightarrow x=\frac{-5}{2}\)
Vậy \(\left[\begin{array}{nghiempt}\frac{3}{4}\\\frac{-5}{2}\end{array}\right.\).
chúc bn hc tốt nha!!!
