Question

what is limit by direct substitution?

Answer 1

Take a look at this: https://cims.nyu.edu/~kiryl/Calculus/Section_1.4--Calculating_Limits/RSimpson-Lecture2.pdf

It is basically this: \[\lim_{x \rightarrow a} f(x) = f(a)\]

Answer 2

WELCOME TO OPENSTUDY! :D

Answer 3

why we use direct substitution?

Answer 4

To find the limits.
When x approaches a value 'a' on a number line, the function f(x) approaches f(a).

Answer 5

Have fun with that.