Question

Evaluate the expression 2n(n-1), when n = = 3 A 11 B 12 C 17 D 18

Answer 1

Answer:

The value of the expression is 12 ⇒ B

Step-by-step explanation:

Let us solve the question

∵ The expression is 2n(n - 1)

→ Simplify it at first by multiply 2n by the bracket (n - 1)

∵ 2n(n - 1) = 2n(n) - 2n(1)

∴ 2n(n - 1) = 2n² - 2n

∵ n = 3

→ Substitute n by 3 in the expression to find its value

∴ 2n² - 2n = 2(3)² - 2(3)

∴ 2n² - 2n = 2(9) - 6

∴ 2n² - 2n = 18 - 6

∴ 2n² - 2n = 12 ⇒ at n = 3

∴ The value of the expression is 12