Question

If a+b=7 and a^3+b^3=91, find the value of ab

Answer 1

Answer:

given,

a + b = 7

and a³ + b³ = 91

since,

a³ + b³ = ( a + b)³ -3ab( a + b)

=> 91 = 7³ -3ab× 7

=> 91 = 343 - 21ab

=> 21ab = 343 -91

=> 21ab = 252

=> ab = 253/21 = 12

so,

ab = 12.

$...$

Answer 2

Step-by-step explanation:

I hope this answer is help you!!..