Answer: Choice A
S9 = (9/2)*(2+26)
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The formula is
Sn = (n/2)*(a1+an)
where
Sn = sum of the first n terms (nth partial sum)
n = number of terms
a1 = first term
an = nth term
In this case,
n = 9
a1 = 2 (plug in n = 1 into the formula an = 3n-1 and simplify)
an = a9 = 26 (plug n = 9 into the formula an = 3n-1 and simplify)
So,
Sn = (n/2)*(a1+an)
S9 = (9/2)*(2+26)
will help us find the sum of the first 9 terms of this arithmetic sequence
Answer:
The domain is all the x-values, and the range is all the y-values
Step-by-step explanation:
Step-by-step explanation:
0.4 x + 3.9 = 5.7
hope 0.4 x = 5.78 - 3.9
0.4x = 1.88
x = 1.88/0.4
x = 4.7
Answer:
Step-by-step explanation:
so first we need to find the height so by splitting the isosceles triangle into two right-angled triangles and then applying Pythagoras' Theorem to one of them.
We now know the height of the triangle and can use this to go back and find the area of the isosceles triangle.
area of triangle = 
x base x height
area of triangle = x 10 x 12
area of triangle = 60
Answer:
I'm pretty sure it's A.
Step-by-step explanation:
the axis of symmetry says x=
so it would have to be and x value
