Respuesta :

gacyber

Explanation:

We want to isolate  

b

in  

a

+

b

+

c

=

180

.

Subtract  

a

from both sides.

a

+

b

+

c

+

−

a

=

180

−

a

b

+

c

=

180

−

a

Now, subtract  

c

from both sides.

b

+

c

−

c

=

180

−

a

−

c

b

=

180

−

a

−

c

a + b - c = 180

add c to both sides:-

a + b = 180 + c

subtract 180 from both sides:_

a + b - 180 =  c      ANswer