(2x + 1) : 7 = 2² + 3²
(2x + 1) : 7 = 4 + 9
(2x + 1) : 7 = 13
2x + 1 = 13 . 7
2x + 1 = 91
2x = 91 - 1
2x = 90
x = 90 : 2
x = 45
\((2x+1):7=2^2+3^2\\\Rightarrow (2x+1):7=4+9\\\Rightarrow(2x+1):7=13\\\Rightarrow2x+1=13\cdot7\\\Rightarrow2x+1=91\\\Rightarrow2x=91-1\\\Rightarrow2x=90\\\Rightarrow x=90:2\\\Rightarrow x=45\\Vậy:x=45\)
(2x+1):7=13
(2x+1) =13 . 7
(2x+1) =91
2x =91-1
2x =90
x =90:2
x =45