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
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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.
There are two solutions to this question, one is positive and the other is negative:
Answer:

Step-by-step explanation:
We can use substitution to find the value of
:




Hope this helps :)
Using the <em>system of equation</em> created, Emily will catch up Lucy after 30 seconds
Given the Parameters :
- Lucy's distance = 2t
- Emily's distance = 5t
<u>We can set up an equation to represent the required scenario thus</u> :
Emily's distance = Lucy's distance + 90
5t = 2t + 90
We solve for t
<em>Collect like terms</em> :
5t - 2t = 90
3t = 90
Divide both sides by 3 to isolate t
t = 90/3
t = 30
Therefore, Emily will catch up with Lucy after 30 seconds
Learn more :brainly.com/question/13218948