Mathematical equation of the second day of junior high school

Question 1: Equation 1: (x+y) (x-y) = 1? x+y= 1/(x-y)

Equation 2: the square of (x-y-1) =4.

So the solution 1)x-y- 1 = 2? x - y =3

Because x+y= 1/(x-y) = 1/3, x = 5/3 y = -4/3.

Solution 2)x-y-1 = -2? x - y = - 1

Because x+y= 1/(x-y) =-1, x=0 y=- 1.

Question 2: Equation 1: (x+3/2y)(x-3/2y)=0.

Equation 2: the square of (x+3/2y) = 1/4.

Solution 1)x+3/2y = 1/2

Substitute in the equation 1: (x+3/2y) (x-3/2y) =1/2× (x-3/2y) = 0? x-3/2y=0

Solution: x= 1/4 y= 1/6.

Solution 2)x+3/2y =-1/2

Substitute in the equation 1: (x+3/2y) (x-3/2y) =-1/2× (x-3/2y) = 0? x-3/2y=0

Solution: x=-1/4 y=-1/6.