Question

If a + b = 4 and ab = -5, then what is the value of a3 + b3?

A) 34 B) 36 C) 124 D) 126

Answer 1

Answer:

✒ Given :

• a + b = 4
• ab = -5

✒ To find :

• a³ + b³

✒ Solution :

By using the suitable Forumula :

(a + b)³ = a³ + b³ + 3ab(a + b)

➡ (4)³ = a³ + b³ + 3(-5)(4)

➡ 64 = a³ + b³ - 60

➡ a³ + b³ = 64 + 60

➡ a³ + b³ = 124

Therefore, the value of a³ + b³ = 124.

Hence, the correct option is C

Step-by-step explanation:

þLÈÄ§È MÄRK MÈ Ä§ ßRÄÌñLÌȧ†✌✌