$(\,5\,b+\,3)\;(\,2\,a+\,5) = $   ?

$\,7\,\,a\,b +\,10\,\,b +\,5\,\,a +\,8$ $\,41\,\,a^2\,b^2 +\,15$ $\,10\,\,a\,b +\,15$ $\,10\,\,a\,b +\,25\,\,b +\,6\,\,a +\,15$

$(\,1+\,b)\;(\,4\,b+\,6) = $   ?

$\,4\,\,b^2 +\,10\,\,b +\,6$ $\,4\,\,b^2 +\,6$ $\,14\,\,b +\,6$ $\,5\,\,b^2 +\,12\,\,b +\,7$

$(\,2+\,2\,y)\;(\,5+\,x) = $   ?

$\,14\,\,x^2\,y^2 +\,10$ $\,2\,\,x\,y +\,10$ $\,7 +\,3\,\,x +\,7\,\,y +\,3\,\,x\,y$ $\,10 +\,2\,\,x +\,10\,\,y +\,2\,\,x\,y$

$(\,3+\,5\,y)\;(\,1+\,y) = $   ?

$\,13\,\,y +\,3$ $\,5\,\,y^2 +\,8\,\,y +\,3$ $\,5\,\,y^2 +\,3$ $\,6\,\,y^2 +\,10\,\,y +\,4$

$(\,4\,t+\,1)\;(\,-2\,x+\,5) = $   ?

$\,8\,\,t\,x +\,20\,\,t \,-2\,\,x +\,5$ $\,-8\,\,t\,x +\,20\,\,t \,-2\,\,x +\,5$ $\,-8\,\,t\,x \,-20\,\,t \,-2\,\,x \,-5$ $\,-8\,\,t\,x +\,20\,\,t \,-2\,\,x \,-5$

$(\,y\,-4)\;(\,2\,-6\,x) = $   ?

$\,2\,\,y \,-6\,\,x\,y \,-8 \,-24\,\,x$ $\,2\,\,y \,-6\,\,x\,y \,-8 +\,24\,\,x$ $\,-2\,\,y \,-6\,\,x\,y \,-8 +\,24\,\,x$ $\,-2\,\,y +\,6\,\,x\,y \,-8 +\,24\,\,x$

$(\,2\,x+\,1)\;(\,6\,-\,x) = $   ?

$\,-2\,\,x^2 \,-13\,\,x \,-6$ $\,-2\,\,x^2 \,-11\,\,x +\,6$ $\,-2\,\,x^2 +\,11\,\,x +\,6$ $\,-2\,\,x^2 +\,13\,\,x +\,6$

$(\,2\,-\,b)\;(\,-6\,-2\,a) = $   ?

$\,-12 \,-4\,\,a \,-6\,\,b +\,2\,\,a\,b$ $\,-12 \,-4\,\,a +\,6\,\,b \,-2\,\,a\,b$ $\,-12 +\,4\,\,a \,-6\,\,b +\,2\,\,a\,b$ $\,-12 \,-4\,\,a +\,6\,\,b +\,2\,\,a\,b$

$(\,2\,y\,-3)\;(\,1\,-2\,y) = $   ?

$\,-4\,\,y^2 \,-8\,\,y \,-3$ $\,-4\,\,y^2 +\,4\,\,y \,-3$ $\,4\,\,y^2 +\,4\,\,y \,-3$ $\,-4\,\,y^2 +\,8\,\,y \,-3$

$(\,4\,y\,-1)\;(\,-5\,-\,y) = $   ?

$\,-4\,\,y^2 \,-19\,\,y \,-5$ $\,-4\,\,y^2 \,-21\,\,y +\,5$ $\,4\,\,y^2 \,-21\,\,y +\,5$ $\,-4\,\,y^2 \,-19\,\,y +\,5$