There is a mound of g pounds of gravel in a quarry. throughout the day, 300 pounds of gravel are added to the mound. two orders of 700 pounds are sold and the gravel is removed from the mound. at the end of the day, the mound has 1,500 pounds of gravel. write the equation that describes the situation. then solve for g.

Step-by-step explanation:

At the start of the day there are g pounds of gravel in the quarry.

Then it says that there were 300 pounds added to the mound, so at this point the pounds of gravel in the mound are now g+300.

Then two orders of 700 pounds are sold and removed from the mound. That means they removed 700 pounds from the mound 2 times. Therefore at this point the pounds of gravel in the mound are now g+300-700-700.

Then it says that at this point, the amount of pounds in the mound are 1500.  Hence we get

To solve for g we just add 700 two times to both sides of the equation, and subtract 300 from both sides of the equation, getting:

And so

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.