1.4k views
1 vote
Solve the equation by completing the square:
3x^2 – 9x = -6

User Digweed
by
6.5k points

2 Answers

6 votes
So my step one would be to add the six over and get 3x squared -9x+6=0, then divide by 3 to get x squared-3x+2=0. The next step is seeing what two numbers multiply to 2 but also add to negative three. The two numbers are -1 and -2. So then you are going to make two equations, one being x-1=0 and the other being x-2=0. Solve both to get X=1 and X=2, check your answers in the original equation. Hope this helps!
User Jacob Wan
by
6.2k points
7 votes
3x^2 - 9x = -6....divide everything by 3

x^2 - 3x = -2
x^2 - 3x + 2.25 = -2 + 2.25
(x - 1.5)^2 = 0.25
x - 1.5 = (+-) sqrt 0.25
x = 1.5 (+-) 0.5

x = 1.5 + 0.5 = 2 <===
x = 1.5 - 0.5 = 1 <===
User Julius Musseau
by
7.0k points
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