$(10+9y)(10-9y) = $   ?

$100 \,- 81\,y^2$ $100 \,+ 81\,y^2$ $100 \,- 81y$ $100\, -180\,y\,+ 81\,y^2$

$(8x+9y)^2 = $   ?

$64\,x^2\, +144\,x\,y\,+ 81\,y^2$ $64\,x^2\, +72\,x\,y\,+ 81\,y^2$ $64\,x^2\, -144\,x\,y\,+ 81\,y^2$ $64\,x^2\,+ 81\,y^2$

$(-10-8y)^2 = $   ?

$100\, +160\,y\,+ 64\,y^2$ $100\, +80\,y\,+ 64\,y^2$ $100\, -160\,y\,+ 64\,y^2$ $-100\, +160\,y\,+ 64\,y^2$

$(3x+y)(3x-y) = $   ?

$9\,x^2 \,- \,y^2$ $9x \,- \,y^2$ $9\,x^2 \,- 2\,y^2$ $9\,x^2 \,- y$

$(4+y)^2 = $   ?

$16\,+ \,y^2$ $16\, +8\,y\,+ \,y^2$ $16\, +8\,y\,+ 2\,y^2$ $16\, +4\,y\,+ \,y^2$

$(7y-6x)^2 = $   ?

$49\,y^2\, -84\,x\,y\,+ 36\,x^2$ $49\,y^2\, -84y\,+ 36\,x^2$ $49\,y^2\, +84\,x\,y\,+ 36\,x^2$ $14\,y^2\, -84\,x\,y\,+ 36\,x^2$