Answer:
3.2
Step-by-step explanation:
x² + xy = 20
Take the derivative with respect to time:
2x dx/dt + x dy/dt + y dx/dt = 20
(2x + y) dx/dt + x dy/dt = 20
Given x = -5, y = 1, and dx/dt = -4:
(2(-5) + 1) (-4) + (-5) dy/dt = 20
(-10 + 1) (-4) − 5 dy/dt = 20
36 − 5 dy/dt = 20
5 dy/dt = 16
dy/dt = 3.2
Hope this helps I guess if not I’m sry
Answer:
by multiplying all numbers seperatly by each other and adding those
Step-by-step explanation:
Answer:

Step-by-step explanation:
First we'll work out the surface area of the pink figure.
That's the area of the two 5 by 6 rectangles on the top and bottom, plus the area of the two 5 by 20 and two 6 by 20 rectangles on the sides.
However, we note that the purple figure is blocking out a 6 by 12 section on the pink figure, so we'll need to subtract this.
The above works out to
.
Then we'll work out the surface area of the purple figure.
This will be the area of the two 4 by 6 rectangles at the top and bottom, plus the area of the two 4 by 12 and one 6 by 12 rectangles on the sides. Note that there's only one 6 by 12 rectangle because the other face is joined to the pink figure, so it's blocked out.
That's
.
So the total surface area is
.