Answer:
740
Step-by-step explanation:
The n th term of an arithmetic series is
= a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Given a₃ = 7 and a₇ = (3 × 7) + 2 = 21 + 2 = 23 , then
a₁ + 2d = 7 → (1)
a₁ + 6d = 23 → (2)
Subtract (1) from (2) term by term
4d = 16 ( divide both sides by 4 )
d = 4
Substitute d = 4 into (1)
a₁ + 2(4) = 7
a₁ + 8 = 7 ( subtract 8 from both sides )
a₁ = - 1
The sum to n terms of an arithmetic series is
= 
[ 2a₁ + (n - 1)d ] , thus
= 
[ (2 × - 1) + (19 × 4) ]
= 10(- 2 + 76) = 10 × 74 = 740
Maybe it the mixed number form. 2 1/2?
Answer:
-4.3 degrees
Step-by-step explanation:
if I understand the problem correctly, then the temperature at midnight fell 15.7 degrees from 11.4 degrees at noon.
11.4 - 15.7 = -4.3 degrees
so, the temperature at midnight was -4.3 degrees
Answer:
The 99% confidence interval for the mean number of hours of part-time work per week for all college students is between 25.8 and 30.2.
Step-by-step explanation:
A confidence interval has the following format.
In which 
is the mean of the sample and M is the margin of error.
In this problem, we have that:
The 99% confidence interval for the mean number of hours of part-time work per week for all college students is between 25.8 and 30.2.
Answer:
Equation 1: x-3y+5=0
Equation 2: 3x+y-1=0
Step-by-step explanation:
Equation 1: x+3y=-5
x+3y+5=-5+5
x=3y+5=0
Equation 2: 9x+3y-3=0
3x+y-1=0
