$(-1+3y)(-1-3y) = $   ?

$1 \,- 6\,y^2$ $1\, -6\,y\,+ 9\,y^2$ $1 \,- 9\,y^2$ $-2 \,- 9\,y^2$

$(9x+7y)(9x-7y) = $   ?

$81\,x^2 \,- 14\,y^2$ $81\,x^2 \,- 7\,y^2$ $81\,x^2\, +126\,x\,y\,+ 49\,y^2$ $81\,x^2 \,- 49\,y^2$

$(6x-8y)^2 = $   ?

$36\,x^2\, -96\,x\,y\,+ 8\,y^2$ $6\,x^2\, -96\,x\,y\,+ 64\,y^2$ $36\,x^2\,- 64\,y^2$ $36\,x^2\, -96\,x\,y\,+ 64\,y^2$

$(-2+5y)^2 = $   ?

$4\, -20\,y\,+ 25\,y^2$ $4\, -10\,y\,+ 25\,y^2$ $4\,+ 25\,y^2$ $4\, -20\,y\,+ 10\,y^2$

$(2x-7)^2 = $   ?

$2\,x^2\, -28\,x\,+ 49$ $4\,x^2\, -14\,x\,+ 49$ $4\,x^2\, -28\,x\,+ 14$ $4\,x^2\, -28\,x\,+ 49$

$(-11x+y)^2 = $   ?

$121\,x^2\,+ \,y^2$ $121\,x^2\, -22\,x\,y\,+ \,y^2$ $121\,x^2\, -22\,x\,y\,+ 2\,y^2$ $121\,x^2\, +22\,x\,y\,+ \,y^2$