Question

Which of the following correctly completes the square for the equation below?

x2 - 9x = 0

Answer 1

If you have x^2+18x=0 then you can write it as x^2+18x+81=81 since I've added 81 to both sides the equation is still complete. With x^2+18x+81 you can factor that down to (x+9)^2 since 9*2=18 and 9^2=81. Hence the whole thing is (x+9)^2=81
Dean M · 5

Answer 2

im confused

Answer 3

What are you confused about?

Answer 4

the whole thing