-19
because 19 is the opposite of -19 as you might have learnt in opposite number
Answer:
13
Step-by-step explanation:

Hope this helps.
Answer:
31
Step-by-step explanation:
31
Answer:
x+75=180
x=180-75
x=105
Step-by-step explanation:
x and a are on a straight line
a straight line=180
so you add the x to a=180
Answer:
n = 2m-4
Step-by-step explanation:
n+2/m-1=2
n+2=2(m-1)
n+2=2m-2
n=2m-2-2
n=2m-4