Question

If a+b=5and ab=6,what is the value of a^-b^?

Answer 1

,

A+B=5 and ab =6. What is the value of a²-b²?

If a + b = 5 then b = 5-a

therefore if ab = 6, then

a * (5-a) = 6

5a - a2 - 6 = 0

-a2 + 5a - 6 = 0

-a2 + 2a + 3a -6 = 0

-a(a-2) + 3(a-2) = 0

(a-2)(-a+3) = 0

So a = 2 or 3

Replacing a with 2 and b with 3, we get:

a + b = 5

2 + 3 = 5

similarly

ab = 6

(2) * (3) = 6

Hence a = 2 and b =3

Therefore value of a2 - b2 is

= 2^2 - 3^3

= 4 - 9

= -5