Respuesta :

apequeno

Answer:  the answer is c

Step-by-step explanation:
a. (21x)-(-16+7x)
21x+16-7x
14x+7
b
(-13n)-(17-5n)
-13n-17+5n
-8n-17

c
(4y-7)-(y-7)
4y-7-y+7
3y

d
(-w+0.4)-(-w-0.4)
-w+0.4+w+0.4
0.8