Answer:
x=9
Step-by-step explanation:
The triangle is equilateral which means the sides are equal.
x+9 = 2x
Subtract x from each side
x+9-x = 2x-x
9 =x
A. would be the answer because if you distribute/factor the expression you would get A.
Answer:
1083 seats
Step-by-step explanation:
this is an arithmetic sequence :
an = an-1 + c
in our case
a1 = 10 (10 seats in the first row)
a2 = a1 + 1 = 10 + 1 = 11
a3 = a2 + 1 = a1 + 1 + 1 = 10 + 1 + 1 = 12
an = an-1 + 1 = a1 + (n-1)×1 = a1 + n - 1 = 10 + n - 1 = 9 + n
a38 = a1 + 37 = 10 + 37 = 47 seats.
altogether this means the sum of the arithmetic sequence of a1 to a38.
the general sum of an arithmetic sequence from a1 to an is
n×(a1 + an)/2
in our case
38×(10 + 47)/2 = 19×57 = 1083 seats
When you subtract flip the signs of the second set.
2x^2+5-4x+3
Now combine like terms
2x^2-4x+8
Final answer: B
