Answer:
x = 2 ±sqrt( 97)
Explanation:
log10(x^2 -4x+7) =2
Raise each side to the base 10
10 ^ log10(x^2 -4x+7) =10^2
x^2 -4x +7 = 100
Subtract 7 from each side
x^2 -4x+7-7 = 100-7
x^2 -4x = 93
Complete the square
-4/2 = -2 (-2)^2 = 4
Add 4 to each side
x^2 -4x+4 = 93+4
(x-2)^2 = 97
Take the square root of each side
sqrt((x-2)^2 )=±sqrt( 97)
x-2 = ±sqrt( 97)
Add 2 to each side
x = 2 ±sqrt( 97)