Answer:
a =4 and b= 3
Step-by-step explanation:
Stare at it for a bit. You have the squre of x, then(ignoring the minus sign) 2 times x times 4. What's left is the square of 4, which is 16; you have 13, you are 3 short. Let's add them to both sides:
[tex]x^2-8x+13+3=3 \rightarrow x^2-8x+16 = 3\\(x-4)^2 = 3[/tex]
so a =4 and b= 3