Assuming 'x' means multiply:
You need to use PEMDAS (parentheses, exponents, multiplication, division, addition, subtraction) :
11 + 5 + (3 x 2) + (8 x 1) {{{{{{{{BECAUSE YOU NEED TO MULTIPLY FIRST}}}}}}}}}}
11 + 5 + 6 + 8 = 30
So, 11 + 5 + 3 x 2 + 8 x 1 = 30