Question -
Answer -
Which of the following equations has 2 as aroot?
(A) x2 – 4x +5 = 0 (B) x2 + 3x – 12 = 0
(C) 2x2 – 7x +6 = 0 (D) 3x2 – 6x – 2 = 0
Solution:
(C) 2x2 – 7x +6 = 0
If 2 is a root then substituting the value 2in place of x should satisfy the equation.
(A) Given,
x2 – 4x + 5 = 0
(2)2 – 4(2) + 5 = 1 ≠ 0
So, x = 2 is not a root of x2 –4x + 5 = 0
(B) Given, x2 + 3x – 12 = 0
(2)2 + 3(2) – 12 = -2 ≠ 0
So, x = 2 is not a root of x2 +3x – 12 = 0
(C) Given, 2x2 – 7x + 6 = 0
2(2)2 – 7(2) + 6 = 0
Here, x = 2 is a root of 2x2 –7x + 6 = 0
(D) Given, 3x2 – 6x – 2 = 0
3(2)2 – 6(2) – 2 = -2 ≠ 0
So, x = 2 is not a root of 3x2 –6x – 2 = 0