. Set an = n(n + 1), n = 1, 2, 3, ···, and form the sequence
S1 = a1
S2 = a1 + a2
S3 = a1 + a2 + a3
.
.
.
Sn = a1 + a2 + a3 + ··· + an
.
.
.
Find a formula for Sn that does not involve adding up the
terms a1, a2, a3, ···. HINT: Use partial fractions to write
1/[k(k + 1)] as the sum of two fractions.

b. would be the answer : )

step-by-step explanation:

step 1: add -16x to both sides.

16x−4y+−16x=64+−16x  

−4y=−16x+64

step 2: divide both sides by -4.

−4y /-4 = -16x + 64/-4

answer:   y=4x−16

hope i'm right

the arc length is found by finding the circumference of the full circle (2xpixradius) and then dividing by 4 to find just one quarter of the circle (90 degrees).

x = 2

step-by-step explanation:

if sr parallel to ba then the sides bc and ac are in proportion, that is

= ← substitute values

= ( cross- multiply )

27x = 6(4x + 1)

27x = 24x + 6 ( subtract 24x from both sides )

3x = 6 ( divide both sides by 3 )

x = 2