Answer:
D. 14.73
Step-by-step explanation:
According to Pythagoras,
19^2 = 12^2 + x^2
x^2 = 19^2 - 12^2
x^2 = 361 - 144
x^2 = 217
x = 
x = 14.73
8x-9y=11
First you move the 8x because you have to leave the 9y alone
8x-9y=11
-8x -8x
-9y=11-8x
Now you have to move the -9, so the inverse of multiplying is dividing so you divide -9.
-9y/-9= 11/-9 -8x/-9
since you can't have negative as a denominator it would be:
y= -11/9+8x/9
<span>You have to change the signs</span>
The gcf of 64 and 16 is16