An employment agency specializing in temporary construction pays heavy equipment operators $ 134 per day and general laborers $ 92 per day. if thirty-eight people were hired and the payroll was $ 4756 , how many heavy equipment operators were employed? how many laborers?

x=heavy equipment

y= general labor

x+y=38

x=38-y

134x + 92y=4756

134(38-y)+92y =4756

5092-134y+92y=4756

-42y = -336

y = -336/-42 = 8

x=38-8=30

check 30*134 =4020

8*92 = 736

4020+736 = 4756

 8 general laborers

30 heavy equipment operators

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.