Answer: answer is C because if you do 2x9 abd 2x3 you 18c-6d and you cant subtract thise cause they have different variables
Step-by-step explanation:
You use the arithmetic sequence formula and input the information given to you.
tn = a + (n-1)d
t(56) is what your looking for so don't worry about the tn.
a is your first term,
a = 15.
n is the position of the term you are looking for, n = 56.
And d is the common difference, you find this by taking t2 and subtracting t1. t2=18 and t1=15.
d = 18 - 15 = 3
Inputting it all into the formula you get,
t(56) = 15 + (56-1)(3)
term 56 = 180.
You use this formula to find any term in a sequence provided you are given enough info. You can also manipulate it if you are asked to find something else like the first term(a), common difference(d) or term position(n). It just depends on what the question is asking and what information you are given. :)
Hope this helps!
Answer:
19cm
Step-by-step explanation:
An equilateral triangle is a triangle where the length of the 3 sides are the same.
the perimeter is the sum of the 3 sides
for example, if the length of the side of the an equilateral triangle is 5, the perimeter is 5 x 3 = 15
let x = unknown length of side
length after increase = x + 5
(x + 5) x 3 = 72
divide both sides of the equation by 3
x + 5 = 24
subtract 5 from both sides of the equation
x = 24 - 5 = 19cm
A cube because it has 6 faces/sides and 12 edges.