What is the roster form of D={x∈N: x²-7x+12=0}?
Answer and explanation
Correct answer: D={3,4}
To find the roster form, solve the defining equation. Factor x²−7x+12 as (x−3)(x−4)=0, so x=3 or x=4. Both values belong to the natural numbers, hence D={3,4}, making option A correct. The values −3 and −4 are not roots, 1 and 12 do not satisfy the equation, and 0 is neither a solution nor a value produced by the factorisation.
Frequently asked questions
What is the correct answer to this question?
D={3,4}
Why is this the correct answer?
To find the roster form, solve the defining equation. Factor x²−7x+12 as (x−3)(x−4)=0, so x=3 or x=4. Both values belong to the natural numbers, hence D={3,4}, making option A correct. The values −3 and −4 are not roots, 1 and 12 do not satisfy the equation, and 0 is neither a solution nor a value produced by the factorisation.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Number Systems.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
