Question

Find the value of a-b if a+b=3 and ab =2

Answer 1

ab=2 a=2/b
So put it in a+b=3.
2/b +b=3
2+b*2=3b
b*2-3b+2=0
b*2-2b-b+2
b(b-2)-1(b-2)
b=2or1
So a=1 or 2
So a-b case (1)
If a is 2 and b is 1
a-b=1
And if b is 2 and a is 1
a-b=-1

Answer 2

we know

(a-b)^2 = (a+b)^2 - 4ab,

substituting values of,
a+b = 3
ab = 2

we get,

(a-b)^2 = 3*3 - 4*2 = 1

a-b = 1 or -1

Hope this helps!