If twice a number is increased by 5 and this sum is multiplied by - 3, the result is - 57. What is the number?

Set it up like this, going from words on the page to letters and variables:

-3 (2x+5) = - 57. Twice a number is 2x, increased by 5 is 2x+5, and that is multiplied by - 3 to get a total of - 57. Distribute the - 3 into the parenthesis to get - 6x - 15 = - 57. Move the 15 over by addition to get - 6x = - 42. Divide both sides by - 6 to get that x = 7