Question

if a square + b square is equal 9 and a b is equal to 4 find the value of 3 (a + b) whole square minus 2( a minus b) whole square.

Answer 1

This is your answer see it

Answer 2

Answer:

Value of the given Expression is 49.

Step-by-step explanation:

Given:

a² + b² = 9   and ab = 4

To find: Value of 3( a + b)² - 2( a - b )²

Consider the identity,

( a - b )² = a² + b² - 2ab

( a - b )² = 9 - 2 × 4

( a - b )² = 9 - 8

( a - b )² = 1

( a - b ) = ± √1

Now, Consider another identity

( a + b )² = a² + b² + 2ab

( a + b )² = 9 + 2 × 4

( a + b )² = 9 + 8

( a + b )² = 17

( a + b ) = ± √17

Finally consider,

3( a + b )² - 2( a - b )²

= 3( ± √17 )² - 2( ± √1 )²

= 3 × 17 - 2 × 1

= 51 - 2

= 49

Therefore, Value of the given Expression is 49.