Question

using y=x2 solve the equation x2-4x+3=0

Answer 1

y = 2x
x = y/2

now,
2x - 4x + 3 = 0
2 (y/2) - 4 (y/2) + 3 = 0
y - 2y + 3 = 0
-y + 3  = 0
-y = -3
y = 3

hence, solved.