Use the FOIL method (First, Outside, Inside, Last)
6r(-8r) = -48r²
6r(-3) = -18r
-1(-8r) = 8r (note: two negatives multiplied together = positive answer)
-1(-3) = 3
-48r² - 18r + 8r + 3
Combine like terms:
-48r² - 18r + 8r + 3
-48r² - 10r + 3
-48r² - 10r + 3 is your answer
hope this helps