Answer:10
Step-by-step explanation:If you add 3 to seven with your fingers you get 10.
A = 80/2 = 40
b = 100/2 = 50
d = 180 - (a+b)
d = 180 - (40+50)
d = 180 - 90
d = 90
Hope it helps :) and let me know if you want me to explain why
Answer:
Step-by-step explanation:
1. no sol
2. infi
3.no sol
4. one sol