9 x 10^7 is how many times as large as 3 x 10^-2

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.

7x+8y=-18, 4x-9y=-3 solve the system of equations

Use set builder notation to represent the following set: { -3, -2, -1, 0}