Question

if a+b=4and ab=3 find a-b

Answer 1

a+b=4

ab=3

Then,

a-b=?

See

a+b=4

ab=3

then

b=3/a

Then

a+3/a=4

a2+3-4a=0

a2-3a-a+3=0

a(a-3)(a-3)

a has two values

a=1,3

Then

ab=3

a=1

1.b=3

b=3

Or

a=3

3.b=3

b=1

Then

a=1orb=3

Or a=3orb=1

Hopes helps u dear

Answer 2

a+b = 4....(1)
ab=3..... (2)
from equation (1)
a=4-b.... (3)
putting equation (3) in (1)
(4-b) b=3
4b-b*b=3
b*b - 4b +3=0
by mid term split
b*b -3b-b +3=0
b(b-3) -1(b-3) =0
(b-3) (b-1) =0
either b-3=0 or b-1 =0
b= 3 or b=1
so a=1 or a=3
so a-b =2 or a-b=-2