ILL GIVE BRAINLIEST! PLEASE HELP I DONT UNDERSTAND!
1 answer:
Answer:
S₁₅ = 645
Step-by-step explanation:
The sum to n terms of an arithmetic sequence is
=
[ 2a₁ + (n - 1)d ]
where a₁ is the first term and d the common difference
Using the nth term formula = 5n + 3 , then
a₁ = 5(1) + 3 = 5 + 3 = 8
a₂ = 5(2) + 3 = 10 + 3 = 13 , then
d = a₂ - a₁ = 13 - 8 = 5
Thus
S₁₅ = [ (2 × 8) + (14 × 5) ]
= 7.5( 16 + 70)
= 7.5 × 86
= 645
You might be interested in
Answer:
slope = 9
Step-by-step explanation:
To find the slope of a line that passes through a pair of points, use the slope formula, . Substitute the x and y values of (-7,-2) and (-6,7) into the formula and simplify:
So, the slope is 9.