How do I solve the quadratic equation by completing the square?! HELP!
x2 + 6x + 34 = 0
2007-12-04 07:19:18 · 3 answers · asked by Babygurl91 1 in Science & Mathematics ➔ Mathematics
x^2 + 6x + (3)^2 = -34 + 9
(x+3)^2 = -25
x+3 = +/-5i
x = -3 +/- 5i
2007-12-04 07:23:04 · answer #1 · answered by norman 7 · 2⤊ 0⤋
x^2 + 6x + 34 = 0
The trick here is, divide the co-efficient of x which is 6 by 2 so 6/2 = 3. Then you write - replace x^2 + 6x part with (x+3)^2
(x+3)^2 + 34 - 9 = 0 ( -9 part comes from 3^2 = 9 meaning sqaure the previous answer you got and subtract it from the whole equation)
Rest must be straightforward. This trick is helpful when dealing with larger numbers. Try some! It works!
(x + 3)^2 = - 34 + 9
(x + 3)^2 = -25
x + 3 = -5i or x + 3 = 5i
x = -3 - 5i or x = -3 + 5i
2007-12-04 09:00:28 · answer #2 · answered by Sayee 4 · 0⤊ 0⤋
x^2 + 6x + 34 = 0
x^2 + 6x = - 34
x^2 + 6x + 9 = - 34 + 9
(x + 3)^2 = -25
x + 3 = -5i or x + 3 = 5i
x = -3 - 5i or x = -3 + 5i
2007-12-04 07:24:32 · answer #3 · answered by ben e 7 · 1⤊ 0⤋