Y=6x (1)
y=5x-7 (2)
Substitute y into (2)
(6x)=5x-7 -- subtract 5x from both sides
x=-7
Sub x into 1
y=6(-7)
y=-42
x=-7
y=-42
Angle 1 and angle 2 are a linear pair, which make a sum of 180
angle 2=180-angle 1=180-70=110
Answer:
60.5 milligrams per square centimeter First, determine how many half lives have expired by dividing the time by the half-life. So: 55/20 = 2.75 That means that only 2^(-2.75) = 0.148650889 = 14.8650889% of the original substance remains. So just divide the amount remaining by 0.148650889 to get the original amount. 9 / 0.148650889 = 60.5445419 So originally, there was 60.5 milligrams per square centimeter 55 years ago.
