Question

a+b=8 and a-b=4 find the value of ab.

Answer 1

Answer:

a + b = 8_________(1)

a-b = 4

2a = 12

a =6  

 

now substitite a value in (1)

6+ b = 8

b=2  

now ab

6(2)= 12  

ab = 12

Step-by-step explanation:

Answer 2

(a-b)²= (a+b)²-2ab

=> 4²=8²-2ab

=>8²-2ab=4²

=>-2ab=4²-8²

=> - 2ab = 16-64

=> - 2ab = -48

=> 2ab = 48 ( as minus sign is in both side )

ab = 24

:)