50.........................
Answer:
<h2>By angle sum property:</h2>
BAC+ABC+BCA=180°
90°+45°+x=180°
135°+x=180°
x=45°=BCA
<h2>since BCA=ABC=<u> </u>45° each </h2><h2>therefore,</h2>

<h2><em><u>Hope </u></em><em><u>it </u></em><em><u>helps</u></em><em><u> you</u></em><em><u><</u></em><em><u>3</u></em></h2>
Because when you multiply by 10, it adds a zero to the end of the number, like 12*10 = 120, so vise versa for dividing
The answer would be 12x^3+ 2x + 4