1) (2x-1)(3x+4)6x^2=16
6x^2+8x-3x-4-6x^2-16=0
5x-20=0
5x=20
x=4
2)(1-2y)(1-3y)=(6y-1)y-1
1-3y-2y+6y^2=6y^2-y-1
1-5y+6y^2-6y^2+y+1=0
-4y+2=0
-4y=-2
y=-2/-4
y=0,5
3) 7+2x^2=2(x+1)(x+3)
7+2x^2=2(x^2+3x+x+3)
7+2x^2=2x^2+8x+6
7+2x^2-2x^2-8x-6=0
-8x+1=0
-8x=-1
x=1/8
4) (y+4)(y+1)=y-(y-2)(2-y)
y^2+y+4y+4=y-(2y-y^2-4+2y)
y^2+5y+4=y-2y+y^2+4-2y
y^2+5y+4-y+2y-y^2+4-2y=0
4y+8=0
4y=-8
y=-8/4
y=-2