how do you find the value of xy if y<0?

Question

these system of equations are given:

x=y^2

6x+9=-3(2y-3)

Answer 1

Start by distributing 2nd equation, and simplifying it.

6x + 9 = -6y + 9

Subtract 9 from both sides

6x = -6y

Divide both sides by 6

x = -y

Now substitute the top equation x= y²

y² = -y

Put everything on left

y² + y = 0

Factor out a y

y(y+1) = 0

so y = 0 or y = -1

SInce y<0, correct answer is y=-1

and x = y² so x = (-1)² = 1

So xy = -1