$(9x+10y)(9x-10y) = $   ?

$18\,x^2 \,- 100\,y^2$ $81\,x^2\, -180\,x\,y\,+ 100\,y^2$ $9x \,- 10y$ $81\,x^2 \,- 100\,y^2$

$(-4+x)(-4-x) = $   ?

$16\, +8\,x\,+ \,x^2$ $16 \,- 2\,x^2$ $16 \,- \,x^2$ $-4 \,- x$

$(9-11y)^2 = $   ?

$81\, +198\,y\,+ 121\,y^2$ $9\, -198\,y\,+ 121\,y^2$ $18\, -198\,y\,+ 121\,y^2$ $81\, -198\,y\,+ 121\,y^2$

$(-5x+9y)^2 = $   ?

$25\,x^2\, -90\,x\,y\,+ 81\,y^2$ $-10\,x^2\, -90\,x\,y\,+ 81\,y^2$ $25\,x^2\, -45\,x\,y\,+ 81\,y^2$ $25\,x^2\, +90\,x\,y\,+ 81\,y^2$

$(-4+12y)^2 = $   ?

$16\, -48\,y\,+ 144\,y^2$ $-8\, -96\,y\,+ 144\,y^2$ $16\, -96\,y\,+ 144\,y^2$ $16\, -96\,y\,+ 12\,y^2$

$(6y-2x)^2 = $   ?

$36\,y^2\, +24\,x\,y\,+ 4\,x^2$ $36\,y^2\, -24\,x\,y\,+ 4\,x^2$ $36\,y^2\, -24\,x\,y\,+ 2\,x^2$ $36\,y^2\,- 4\,x^2$