What is x^2-24x+144 equal to?
Answer and explanation
Correct answer: (x-12)^2
x^2-24x+144 can be written as x^2-2\cdot x\cdot12+12^2 . Using the identity a^2-2ab+b^2=(a-b)^2 , it becomes (x-12)^2 . Option B would produce a positive middle term, so it is incorrect. Exam tip: take the square roots of the first and last terms and then check the sign of the middle term.
Frequently asked questions
What is the correct answer to this question?
(x-12)^2
Why is this the correct answer?
x^2-24x+144 can be written as x^2-2\cdot x\cdot12+12^2 . Using the identity a^2-2ab+b^2=(a-b)^2 , it becomes (x-12)^2 . Option B would produce a positive middle term, so it is incorrect. Exam tip: take the square roots of the first and last terms and then check the sign of the middle term.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Polynomials. Topic: Operations on real numbers and the laws of exponents.
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