Solve the two-step equation. -9x + 0.4 = 4

Which operation must be performed to move all the constants to the right side of the equation?
A. Add 0.4
B. Add 4
C. Subtract 0.4
D. Subtract 4

Then, which operation must be performed to isolate the variable?
A. Add -9 on both sides
B. Subtract -9 on both sides
C. Multiply by -9 on both sides
D. Divide by -9 on both sides

The solution to the equation is x = .