Question

. If (a − b) = 3 and ab = 5, find the value of
(a) a ^2 + b^2
(b) a^4 + b^4

Answer 1

Step-by-step explanation:

(a-b) = 3

squaring both sides,

(a-b)² = 3²

We know that,

(a-b)² = a²-2ab+b²

So,

a²-2ab+b²=9

a²+b² = 9+2ab

It is given that, ab = 5

So,

a²+b²=9+(2×5)

a²+b² = 9+10 = 19