Question

find value of x and y, xy =20 ,x-y =-1​

Answer 1

here x-y=-1-------->(1)

form x=-1+y

given xy=20-------->(2)

substitute x=-1+y in (2)

=(-1+y)*y=20

=-y+y²=20

=y²-y-20=0

By factorisation y=5 or y=-4

substitute y=-4 in (1)

x-y=-1

=x-(-4)=-1

=X+4=-1

x=-1-4

X=-5

here x=-5 and y=-4