Question

What is the intermediate step in the form (x + a)2 = b as a result of completing the

square for the following equation?
5x2 – 168 = -60x + 12

Answer 1

`(x+6)^(2)` = 51

Explanation:

5x2 – 168 = -60x + 12

5x2 + 60 x – 180 = 0

`x^(2)` + 12 x – 15 = 0

`x^(2)` + 12 x = 15

+ 36 + 36

`x^(2)` + 12 x + 36 = 51

`(x+6)^(2)` = 51

`\sqrt{(x+6)^(2) }` =
`√(51)`

x + 6 =
`√(51)`

x = -6 ±
`√(51)`

Answer 2

5x2 – 168 = -60x + 12

5x*2 – 156 = -60x

-55x*2=156

55x=-78

x=-1.41818181818

also know as 18/7 or 1 4/7