\(175-75:\left(x+1\right)\times2=145\\ \Rightarrow75:\left(x+1\right)\times2=30\\ \Rightarrow75:\left(x+1\right)=15\\ \Rightarrow x+1=5\\ \Leftrightarrow x=4\)
Vậy x = 4
175 - 75 : ( x + 1) x 2 =145
75 : ( x+1) x 2 = 175-145
75:(x+1) x 2= 30
75:(x+1) = 30 : 2
75 : ( x+1)= 15
x+1 = 75:15
x+1 = 5
x = 5-1=4