Help with this please

Which is the most efficient first step to solve x in the equation 3.7x - 18 = -4.3x -34 a. add 3.7x to both sides of the equation. b. add 4.3x to both sides of the equation. c. subtract 18 from both sides of the equation. d. subtract 34 from both sides of the equation.

7. if the value of x varies directly with the value of y, and x = 3 when y = 21. what is the valu y, and x = 3 when y = 21. what is the value of x when y = 105?

In the xy-plane, if the parabola with equation passes through the point (-1, -1), which of the following must be true?