Which system models the given situation? Darnell has quarters and nickels that total $20. There are a total of 100 coins. o A. x + y = 20
.25x + .05y = 100
o B. X+ y = 20
25x + .50y = 100
O C. X + y = 100
.25x +.05y = 20
O D. x + y = 100
.25x +.5y = 20

∆abc is reflected across the x-axis and translated 2 units up to give the image ∆a'b'c' with coordinates a'(1, 1), b'(2, -1), c'(2, 1). what are the coordinates of the preimage ∆abc? a. a(-1, 1), b(-2, 3), c(-2, 1) b. a(1, 1), b(2, 3), c(2, 1) c. a(1, -3), b(2, -1), c(2, -3) d. a(1, -3), b(2, -5), c(2, -3)

Determine whether the following statements are true and give an explanation or counterexample. bold a. when using the shell method, the axis of the cylindrical shells is parallel to the axis of revolution. bold b. if a region is revolved about the y-axis, then the shell method must be used. bold c. if a region is revolved about the x-axis, then in principle it is possible to use the disk/washer method and integrate with respect to x or the shell method and integrate with respect to y.

Find the area of the surface obtained by rotating the curve z=4e^2y from y = 0 to y =1 about the y-axis. the area is square units