Question

Q, Fixed a system of coordinates in the plane, conficer the curve C having equation y = (x-2)^2. The line x + y - 2 = 0 intersects C in:

(A)1 poin

(B) no point

(C) 2 points

(D) infinitely many points

3 points

Answer 1

C

Explanation:

y = (x - 2)² = x² - 4x + 4 → (1)

x + y - 2 = 0 → (2)

substitute y = x² - 4x + 4 into (2)

x + x² - 4x + 4 - 2 = 0

x² - 3x + 2 = 0

(x - 1)(x - 2) = 0

equate each factor to zero and solve for x

x - 1 = 0 ⇒ x = 1

x - 2 = 0 ⇒ x = 2

substitute these values into (2) and solve for y

x = 1 : 1 + y - 2 = 0 ⇒ y - 1 = 0 ⇒ y = 1 ⇒ (1, 1 )

x = 2 : 2 + y - 2 = 0 ⇒ y + 0 = 0 ⇒ y = 0 ⇒ (2, 0 )

the line intersects curve C at 2 points (1, 1 ) and (2, 0 )