Answer:
6 days
Step-by-step explanation:
pay 60 = -60
Let d = the number of days
30d - 60 = sister
20d = me
Equation:
30d - 60 = 20d Move 30 to the other side
-30d -30d
-60 = 20d - 30d Combine liked terms
-60 = -10d
-10 -10 Divide
d = 6
1600<2570-125.5x<2000 subtract 2570 from all terms...
-970<-125.5x<-570 divide all terms by -125.5 (and reverse signs because of division by a negative!)
7.73>x>4.54 and x is months since January, and since months can only be integers...
x=[5,7]
So January + 5, 6, and 7 respectively are the three months that satisfy the equation...
June, July, and August.
Answer: 
Step-by-step explanation:
Using the values
and
, the slope is
.
So, the equation is:
