If a+b =6 and ab =4 then what is the value of a3 + b3.

by

Option

A) 120

B) 125

C) 144

D) 81

Detailed solution

We know that a+b=6 and ab=4.

Using (a+b)2 = a2 + b2 + 2ab

a2 + b2 = (a+b)2 -2ab

a2 + b2 = 62 -2×4

a2 + b2 = 28

Using

(a3 + b3) = (a+b) (a2 + b2 – ab)

= ( 6 ) ( 28 – 4)

= 144

ANSWER 44

The market price of an item was Rs 480 but shopkeeper offered discounts of 5%. At what price does he finally sell the item.

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