Explanation

$$lim_{x to a} (2x + 4)$$

Assuming the question meant:

lim​ x→3 ​(2x+4)

Then:

$$lim_{x to 3} (2x + 4) = 2(3) + 4 = 6 + 4 = 10$$x→3 (2x+4)=2(3)+4=6+4=10