To simplify the expressions you have to combine the like terms.
This means that you'll solve the operations between the terms that have the same variables, for example x + 2x=3x
Or the terms that have no variables and are only numbers, for example 4+5=9
a. The expression is
Both terms have the same variable "x", so you can add them together. To do so, add the coefficients, i.e. the numbers that are being multiplied by x
And you get that the simplified expression is 7x
b. The expression is
In this expression you have two types of terms, the x-related terms and one constant. In this case you have to solve the operation for the x-related terms together and leave the constant as it is
The simplified expression is 8x-1