a ) y(y+3)-y²-10=30
y x y + y x 3 -y²-10=30
y² + 3y -y²-10=30
3y -10=30
3y -10 + 10 = 30 + 10
3y = 40
3y/3 = 40/3
y = 40/3
b) (x+2)(x-3)=x²+3
x² -3x + 2x -6 = x²+3
x² -3x + 2x -6 - x² = x²+3 - x²
-3x + 2x -6 = 3
-x - 6 + 6 = 3 + 6
-x = 9
x = -9
voila ^^