Question

How can x2 = x2 + 2x + 9 be set up as a system of equations?
a)
y = x2 - 9
y = x2 + 2x + 9

b)
y = x2
y = x2 + 2x + 9

c)
y = x2 + 2x
y = x2 + 9

d)
y = x2
y = 2x + 9

Answer 1

if a = b, then you can set up this system of equations

y = a
y = b

Answer 2

notice if you start with y = a and replace 'y' with 'b' (since y = b), you get b = a or a = b back again