The limit in the post is [imath]\displaystyle \mathop {\lim }\limits_{x \to \infty } \left( {1 - \frac{1}{{4x}}} \right)\exp ( - {x^2} + 5x - 6)[/imath]

\(\displaystyle \ (1 - 1/4x) \ \) is the same as \(\displaystyle \ (1 - \tfrac{1}{4}x) \ \) because of the Order of Operations. I would

not write it that way as the former, because I want to emphasize the fraction. In

horizontal style I would write it as \(\displaystyle \ \) (1 - (1/4)x) \(\displaystyle \ \) or \(\displaystyle \ \) [1 - (1/4)x].

For a corresponding example, if you enter "1 - 1/4x = 0" into WolframAlpha or other

linear equation solving sites where the display shows it as a horizontal style, you'll

see the solution is x = 4, but not x = 1/4.

To get \(\displaystyle \ \bigg(1 - \frac{1}{4x} \bigg), \ \) I would expect that to be indicated in horizontal style using most likely parentheses such as this: \(\displaystyle \ \ \) (1 - 1/(4x))\(\displaystyle \ \) or \(\displaystyle \ \) [1 - 1/(4x)], because the denominator

of 4x needs the grouping symbols in that case.