For any two numbers a and b, the operation ‘★’ is defined as a ★ b = a2 – 2b. What is the value of 7 ★ 9?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 31
Put the first number in place of a and the second number in place of b in the rule a ★ b = a2 – 2b.
Here a = 7 and b = 9
\(a^2=7^2=49\)
\(2b=2\times9=18\)
7 ★ 9 \(=49-18=31\)