Buzz: Questions & Answers

I'm trying to create an answer space for students to use for the quadratic formula. Here is an image of my attempts so far: Hmmm, it seems I can no longer insert images in discussions. I know the actual answer spaces must have boxes around them. I like that. What I don't like are the light gray lines around the whole table and the vertical line after the x=. They make it more difficult to see the equation as a whole. In the bottom image I'm missing the answer blank inside the radical because Buzz won't recognize an answer blank inside of an equation. That's why in the first attempt (question 3 below) I had to put the empty radical in a cell with the answer blank in the next cell with a top border to emulate the top of the radical symbol. If you had a way to make that part look better it would also be appreciated. Maybe if I made the cell with the radical symbol taller or used a larger point size? I'm a novice at HTML and don't really know what I'm doing. I thought the border-collapse would do it, but that doesn't seem to do anything in this case. I also tried no-border and border = 0px. All to no effect. Looking at some of your code I see this command: class="fr-table-no-border". That seems to prevent the borders I want from showing up though. Here is my code for those two attempts (note I replaced the h t m and l with XXXX because it was trying to read the code and messing up the post):

Type: F, Number
Options: Multiple
Var: a = 2
Var: b = 3
Var: c = 4
3) [XXXX]`$a$x^2+$b$x-$c$`
<br>
<br>
<table style="border-collapse: collapse"><tbody><tr><td rowspan="2">`x=`</td>
<td style="border-bottom: 2px solid black;padding-bottom: 2px;">___`+-sqrt`</td><td style="border-top: 1px solid black;border-bottom: 2px solid black">___</td>
</tr>
<tr><td colspan="3" style="padding-top: 2px;text-align:center">___</td>
</tr></tbody></table>[XXXX]
a. eval(-1*$b$)
b. eval($b$^2-4*$a$*$c$)
c. eval(2*$a$)
Type: F, Number
Options: Multiple
Var: a = 2
Var: b = 3
Var: c = 4
4) [XXXX]`$a$x^2+$b$x-$c$`
<br>
<br>
<table style="border-collapse: collapse"><tbody><tr><td rowspan="2">`x=`</td>
<td style="border-bottom: 2px solid black;padding-bottom: 2px;">___<a:math>+-sqrt(___)</a:math></td>
</tr>
<tr><td colspan="3" style="padding-top: 2px;text-align:center">___</td>
</tr></tbody></table>[XXXX]
a. eval(-1*$b$)
b. eval($b$^2-4*$a$*$c$)
c. eval(2*$a$)