Code has already been provided to create the four variables $a,b,c,$ and. $d.$ Add commands to evaluate the following expressions using these variables and assign the results to the indicated variable names:

$A_1=\frac{a+b}{c-d}$

Assign the result for $A_1$ to the variable Answer $1.$

$A_2=\sqrt[\phantom{2}]{\frac{a+bc}{d}}$

Assign the result for $A_2$ to the variable Answer $2.$

$A_3=(a-c)(a+b{)}^d$

Assign the result for $A_3$ to the variable Answer $3.$