$(\,2+\,b)\;(\,6\,a+\,3) = $   ?

$\,21\,\,a^2\,b^2 +\,6$ $\,8\,\,a +\,5 +\,7\,\,a\,b +\,4\,\,b$ $\,12\,\,a +\,6 +\,6\,\,a\,b +\,3\,\,b$ $\,6\,\,a\,b +\,6$

$(\,3+\,2\,t)\;(\,t+\,4) = $   ?

$\,2\,\,t^2 +\,12$ $\,2\,\,t^2 +\,11\,\,t +\,12$ $\,13\,\,t +\,12$ $\,3\,\,t^2 +\,10\,\,t +\,7$

$(\,3+\,b)\;(\,1+\,6\,a) = $   ?

$\,3 +\,18\,\,a +\,\,b +\,6\,\,a\,b$ $\,4 +\,9\,\,a +\,2\,\,b +\,7\,\,a\,b$ $\,6\,\,a\,b +\,3$ $\,25\,\,a^2\,b^2 +\,3$

$(\,2+\,3\,y)\;(\,3+\,y) = $   ?

$\,3\,\,y^2 +\,11\,\,y +\,6$ $\,14\,\,y +\,6$ $\,4\,\,y^2 +\,9\,\,y +\,5$ $\,3\,\,y^2 +\,6$

$(\,1+\,x)\;(\,-4+\,5\,y) = $   ?

$\,-4 +\,5\,\,y \,-4\,\,x +\,5\,\,x\,y$ $\,4 +\,5\,\,y \,-4\,\,x +\,5\,\,x\,y$ $\,4 +\,5\,\,y +\,4\,\,x +\,5\,\,x\,y$ $\,-4 \,-5\,\,y \,-4\,\,x +\,5\,\,x\,y$

$(\,3\,x\,-5)\;(\,-6+\,y) = $   ?

$\,-18\,\,x +\,3\,\,x\,y \,-30 \,-5\,\,y$ $\,-18\,\,x \,-3\,\,x\,y +\,30 +\,5\,\,y$ $\,-18\,\,x +\,3\,\,x\,y \,-30 +\,5\,\,y$ $\,-18\,\,x +\,3\,\,x\,y +\,30 \,-5\,\,y$

$(\,5\,x+\,2)\;(\,2\,x\,-3) = $   ?

$\,-10\,\,x^2 \,-11\,\,x +\,6$ $\,10\,\,x^2 \,-11\,\,x \,-6$ $\,-10\,\,x^2 +\,19\,\,x \,-6$ $\,10\,\,x^2 \,-19\,\,x +\,6$

$(\,6\,-4\,t)\;(\,-4\,-\,x) = $   ?

$\,-24 \,-6\,\,x +\,16\,\,t +\,4\,\,t\,x$ $\,24 +\,6\,\,x +\,16\,\,t +\,4\,\,t\,x$ $\,-24 \,-6\,\,x +\,16\,\,t \,-4\,\,t\,x$ $\,24 \,-6\,\,x +\,16\,\,t +\,4\,\,t\,x$

$(\,6+\,4\,t)\;(\,-\,t\,-3) = $   ?

$\,-4\,\,t^2 +\,6\,\,t +\,18$ $\,4\,\,t^2 \,-6\,\,t \,-18$ $\,-4\,\,t^2 +\,6\,\,t \,-18$ $\,-4\,\,t^2 \,-18\,\,t \,-18$

$(\,3\,-2\,t)\;(\,-6\,t\,-1) = $   ?

$\,12\,\,t^2 \,-16\,\,t \,-3$ $\,12\,\,t^2 +\,20\,\,t \,-3$ $\,-12\,\,t^2 \,-16\,\,t \,-3$ $\,12\,\,t^2 +\,16\,\,t \,-3$