Answer:
Step-by-step explanation:
a1 = 3(1) - 7 = - 4
a2 = 3(2) - 7 = -1
d = a2 - a1
d = -1 - (-4)
d = -1 + 4
d = 3
a60 = 3(60) - 7
a60 = 180 - 7
a60 = 173
n = 60
Sum = (a1 + a60) * n / 2
Sum = (-4 + 173) * 60/2
Sum = (169)*30
Sum = 5070
==================
Just to check, we'll use the second summation formula
d = 3
n = 60
a1 = -4
Sum = (2*a1 + (n - 1)*d )*n / 2
Sum = (2*(-4) + (60 -1)*3)* 60/2
Sum = (-8 + 59*3) * 30
Sum = (177 - 8)*30
Sum = 169 * 30
Sum = 5070
Same answer.
Answer:
Dennis paid $82 and Connie paid $46.
Step-by-step explanation:
We can set up an equation by putting in variables, c representing how much Connie paid. Since we know that Dennis paid $36 more, we will also factor that in the equation.
c + c + 36 = 128
Where c + 36 represents the amount Dennis paid, and 128 represents the total amount paid as given in the question. We can start by adding like terms. 2c + 36 = 128
Now, we can subtract 36 from each side,
2c + 36 - 36 = 128 - 36
2c = 92
Divide each side by two,
2c/2 = 92/2
c = 46
Now, to make sure this is correct, let's substitute our c for 46 in our equation:
46 + 46 + 36 = 128
92 + 36 = 128
128 = 128
Therefore, our equation is correct, and Dennis paid $82 while Connie paid $46.
Answer:
Step-by-step explanation:
The perimeter is 58 units long
Answer:
Step-by-step explanation:
Polygons (shapes made of straight lines) where no angle is greater than 180 degrees. If even one angle is greater than 180 then it is a concave polygon.
Answer:
D' (1, 3)
Step-by-step explanation:
When reflected across the y = x line, the "x" and "y" coordinates switch.
If D is (3, 1), then:
x = 3
y = 1
Switch the "x" and "y" values, and rewrite as (x, y).
x = 1
y = 3
D' (1, 3)
