If (5^(k-1))+(5^(k+1)) = m, what is 2*5^k in terms of m? If , what is in terms of m?

A) 5m

B) 5m÷2

C) 5m÷13

D) 5m÷26

5m

Step-by-step explanation:

5^(k-1)+5^(k-1)=m

Going to combine like terms on left:

2×5^(k-1)=m

Law of exponents applied:

2×5^k×5^(-1)=m

Reciprocal:

2×5^k×1/5=m

Multiply 5 on both sides to obtain the requested:

2×5^k=5m

3. parallelogram

step-by-step explanation:

we turn each of our sides into direction vectors

ab=b-a=(3 - 7, 1 - 0) = (-4, 1)

bc=c-b=(1,6)

cd=d-c=(4,-1)

da=a-d=(-1,-6)

we see how the opposite sides have negated direction vectors; this is characteristic of a parallelogram.   we have congruent sides ab=cd and bc=da with unequal lengths because 1^2+6^2 is different from (-4)^2+1^2.   so it's not a square or a rhombus.  

we check the dot product of direction vectors of adjacent sides.   we have

ab dot bc = -4(1) + 1(6) = 2

that's not zero so the sides are not perpendicular.   we've ruled out rectangle.

the direction vectors indicate two pairs of congruent parallel sides, so we choose parallelogram over trapezoid.

the correct is answer is a 9-sided polygon!