Factorise the following expression x^2+11x+24=0

Find two values that multiply together to make 24, and add together to make 11
List the factors of 24:24,112,26,48,3
Here we can see the only numbers that add together to make 11 are 8 and 3, so these are the numbers we place at the end of each bracket
(x+8)(x+3)