Question

X + Y = 1 and xy =minus 12 find x minus y and x square minus y square

Answer 1

(x+y) = 1
(x+y)² = x²+y²+2xy
(1)² = x²+y²+2(-12)
1 = x²+y²-24
25 = x²+y²

(x-y)² = x²+y²-2xy
(x-y)² = 25-2(-12)
(x-y)² = 25+24 => 49
(x-y) = √49 = 7

we know that ,
x²-y² = (x+y)(x-y)
x²-y² = 1(7) => 7
hope this helps

Answer 2

x + y = 1 , xy =-12 
[x+y]2 = x2 + y2 +2xy
1 sq. = x2 + y2 + 2 [-12]
1 = x2 + y2 - 24
1+24 = x2 + y2
x2 + y2 = 25 
after finding the value x2 + y2 we can substitute the value 

[ x-y ] 2 = x2 + y2 - 2xy
[x - y]2 = 25 - 2 [-12]
[x - y]2 = 25 + 24
x - y = square root of 49
which is = to 7
and [x - y]2 = 49......
i hope it helps