\(a.3x-75=45+3\times\left(-25\right)\)
\(3x-75=45+\left(-75\right)\)
\(3x-75=-30\)
\(3x=-30+75\)
\(3x=45\)
\(x=45:3\)
\(x=15\)
Vậy \(x=15\)
\(b.\frac{x}{3}=\frac{2}{3}+\frac{-1}{7}\)
\(\frac{x}{3}=\frac{11}{21}\)
\(\Rightarrow\frac{x\times7}{21}=\frac{11}{21}\)
\(\Rightarrow x\times7=11\)
\(x=11:7\)
\(x=\frac{11}{7}\)
\(\Rightarrow\)\(x\)không thỏa mãn
Vậy \(x\in\varnothing\)
a) 3x-75=45+3.(-25)
\(\Rightarrow3x-75=45+\left(-75\right)\)
\(\Rightarrow3x-75-45+75=0\)
\(\Rightarrow3x-45-75+75=0\)
\(\Rightarrow3x-45=0\)
\(\Rightarrow3x=45\)
\(\Rightarrow x=\frac{45}{3}=15\)
Vậy: \(x=15\)
b) \(\frac{x}{3}=\frac{2}{3}+\frac{-1}{7}\)
\(\Rightarrow\frac{x}{3}=\frac{14}{21}+\frac{-3}{21}\)
\(\Rightarrow\frac{x}{3}=\frac{11}{21}\)
\(\Rightarrow x=\frac{3.11}{21}=\frac{33}{21}\)
Vậy: \(x=\frac{33}{21}\)
a) 3x - 75= 45 + 3.(-25)
3x - 75= 45 + (-75)
3x - 75= -30
3x = -30 + 75
3x = 45
x= 45 : 3
x = 15
Vậy x = 15
b) x/3 = 2/3 + (-1)/7
x/3 = 14/21 + (-3)/21
x/3 = 9/21
21x= 9.3
x = 9.3/21
x = 9/7
Vậy x = 9/7
b) x/3 = 2/3 + (-1)/7
x/3= 14/21 + (-3)/21
x/3= 11/21
21x= 11.3
x= 11.3/21
x= 11/7
Vậy x= 11/7
