'The sum of a number and 4': let's call the number 'x'. This part is translated as:
[tex]x+4[/tex]'Eight times the sum of a number and 4'. This is 8 times the previous expression:
[tex]8\cdot(x+4)[/tex]'Eight times the sum of a number and 4 is 3'. Now it's said that this expression equals 3:
[tex]8\cdot(x+4)=3[/tex]