Find the term named in the problem, and the explicit formula. -32,-132,-232,-332,… find a40

We need to find the n term formula:

The given sequence represents an arithmetic sequence and it follows the next form:

Where a represents the first term, in this case, a= -31

n is the term of the sequence

And d is the constant:

Let's find the constant

a1 to a2 =

-32 to -132, then, -32 needs -100 units bo equal to -132.

Now, -132 need -100 units to be equal to -232.

-232 needs -100 units to be equal to -332

Therefore, the constant d is equal to -100, d=-100

Replacing these values:

Then:

With this n formula, we can replace n=40, then, we will find a40:

Therefore:

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.