In ( (z-8)^2=z^2-16z+__ ), what is the blank?
Answer and explanation
Correct answer: 64
Use the identity \((a-b)^2=a^2-2ab+b^2\). Here, \(a=z\) and \(b=8\), so \((z-8)^2=z^2-2(z)(8)+8^2=z^2-16z+64\). Therefore, the blank is 64. The number 16 is related to the coefficient of the middle term, not the last term. Exam tip: in \((a-b)^2\), the last term is always \(b^2\), so it is positive.
Frequently asked questions
What is the correct answer to this question?
64
Why is this the correct answer?
Use the identity \((a-b)^2=a^2-2ab+b^2\). Here, \(a=z\) and \(b=8\), so \((z-8)^2=z^2-2(z)(8)+8^2=z^2-16z+64\). Therefore, the blank is 64. The number 16 is related to the coefficient of the middle term, not the last term. Exam tip: in \((a-b)^2\), the last term is always \(b^2\), so it is positive.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Exploring Algebraic Identities. Topic: Algebraic identities.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
