77
60+72+77+70 = 288/4 = 72*.4 = 28.8
46.2 points to get 75
set up proportion:
60/100 = 46.2/x
x = 77
I'm sure there's an easier method but that's just my thought process
Answer:
1
Step-by-step explanation:
t=13.28382 ≈ 13.3 years
x=3
2x²+4=22
-4 -4
2x²=18
2 2
x²=9
=
X=3