Linear Equation in One Variable  Linear Equation in Two Variables 

There is only one variable  There are Two Variables 
Power of variable is equal to One  Here also, power of variables is equal to one 
Linear Equation in One variable has a unique solution  Linear equation in two variables has infinitely many solution 
Examples: 2x = 20 4a + 1 = 7 9/p = 81 8q  10 = 2p
 Examples: a  b = 20 2p + 10 = 5q m + 9n = 18 4r  3s = 0
