Michael B. answered 01/31/13
Seasoned and experienced tutor with extensive science background
For these questions just read the sentence and make an equation from what you are given.
Let x = "a number"
Now,
three * (a number) + one = nineteen
3x + 1 = 19
subtract 1 from both sides
3x +1 -1 = 19 -1
divide both sides by 3
3x/3 = 18/3
x = 6