Answer:
15 :)
Step-by-step explanation:
So first, we want to substitute in 15 to all the x variables.
So,
3x - 8y = 5
Becomes
3 * 15 - 8y = 5
Or,
45 - 8y = 5
So here, you can subtract 45 from both sides to move all like terms to one side.
-8y = 5 - 45
And then simplify:
-8y = -40
Then divide both sides by -8
y = 5
The missing side is 17 and rounded it is 20

AS we know COSINE =PERPENDICULAR /BASE
SO ACCORDING TO ABOVE IMAGE
PERPENDICULAR is 5 ft
AND BASE
is 8 ft
so now cosine A = 5/ 8
MEAN THE CIRRECT ANSWER IS (D)
HOPE IT HELPED YOU