The literal translation of the condition to an equation is this 2*(x + 6) = x - 7. Simplify and solve for x: 2x + 12 = x - 7 2x - x = -7 - 12 x = -19. Answer. The number under the question is -19. Check. The sum of the number and 6 is -19+6 = -13. When doubled, -13 becomes -26. 7 less than the number is -19 - 7 = - 26. ! Correct !