For what value of x is the tangent to the curve y = x(^2) – 4x + 3 parallel to the xaxis?

A.
3 
B.
2 
C.
1 
D.
6
Correct Answer: Option B
Explanation
At the point where the tangent is parallel to the x axis, the slope of the curve = 0.
Given: (y = x^{2} – 4x + 3)
(frac{mathrm d y}{mathrm d x} = 2x – 4)
(2x – 4 = 0 implies 2x = 4 )
(x = 2)
When x = 2, the tangent of the curve is parallel to the x axis.