Verified Answer :

In simplifying variables and coefficients, you just have to add or subtract the coefficients with the same terms. The terms are the same when they both have the variable x and exponent.
Example 1:
       \(5x^2 + 6x^2 = 11x^2\)
You can simply add 5 and 6 and copy variable x^2 because they are similar terms.
But for expression \(4x^2 + 6x\), coefficients 4 and 6 cannot be added because they are not the same terms.

Example 2:
Simplify
   \(8x^2 +3x -2x^2 + 6 + 4x - 5
   = 6x^2 +7x + 1\)