If I understand you correctly, that is called in-line code, and yes, it is possible, see this simple example.
---
title: "test"
output: html_document
---
```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
model <- lm(Sepal.Length ~ Sepal.Width, data = iris)
alpha <- model$coefficients[[1]]
```
## Linear Model
This is the intercept using in-line code `r alpha`
