Answer:
x^2 - 5x + 8 = (x - 5/2)^2 + 7/4
Step-by-step explanation:
(x - a)^2 + b = x^2 - 2ax + a^2 + b
equate to your quadratic :
x^2 - 5x + 8 = x^2 - 2ax + (a^2 + b)
equating coefficients (ignoring x^2 as the coefficient is 1 for both)
for x :
-5 = -2a --> a = 5/2
for x^(0) : 8 = a^2 + b , note a = 5/2
thus,
8 = (5/2)^2 + b
8 = 25/4 + b
b = 8 - 25/4 = 32/4 - 25/4 = (32 - 25)/4 = 7/4
hence a = 5/2 , b = 7/4
thus,
x^2 - 5x + 8 = (x - 5/2)^2 + 7/4
