Answer: 4
Concept:
Here, we need to understand the idea of evaluation.
When encountering questions that gave you an expression with variables, then stated: "If x = a, y = b, z = c" (a, b, c are all constants), this means you should substitute the value given for each variable back to the expression.
Solve:
Given information
x = 3
Given expression
(3x + 8) - (2x + 7)
Substitute values in the expression
=(3 (3) + 8) - (2 (3) + 7)
Simplify by multiplication in parentheses
=(9 + 8) - (6 + 7)
Simplify by addition
=17 - 13
Simplify by subtraction
=
Hope this helps!! :)
Please let me know if you have any questions