Answer:

It is given that a+b = 10 and ab = 21. 102 = a2 + 2(21)+b2. i.e. 100 = a2 + b2 + 42, a2+ b2= 100 -42 = 58.

Step-by-step explanation:

Answer:

Hope this helps

Step-by-step explanation:

It is given that a+b = 10 and ab = 21.

Since (a+b)2 = a2 +2ab +b2,

While substituting we get

102 = a2 + 2(21)+b2.

i.e. 100 = a2 + b2 + 42,

a2+ b2= 100 -42 = 58.

Now,

a2 + b2 = (a − b)2 + 2ab  

(a − b)2  = [a2 + b2] - 2ab

(a − b)2  = 58 - 2X21

               = 58 - 42

               =  16