Nonlinear because the first differences are all different
Answer:

Step-by-step explanation:
First open the brackets

Then collect the like terms

Solve the like terms

The simplified form is

3 + [_] ÷ 7 = 9
[_] ÷ 7 = 9 - 3
[_] = 6 x 7
[_] = 42
to check, just put 42 in the empty place and solve
Answer:
10x + 6
Step-by-step explanation:
3x - 5 + 7x + 11
10x - 5 + 11
10x + 6