Answer:
i believe it is -21, but i'm not sure
Step-by-step explanation:
just foil the two to get a quadratic expression
Answer: Your answer is 0 (F.O.I.L) first. outer. inner. last. Or you could use what my teacher calls the magic box
Step-by-step explanation:
So for the boxes you multiply for example the top left box you multiply the 9 above it and the 9 to the left or like the top right box you multiply the -9 above it and the 9 on the outside of the box to the left
You can use any letter but when you label it x you find x
0.75x-18.5=0.65x
0.75x-0.65x=18.5
0.1x=18.5
x=18.5/0.1=185
Answer: x=185
To checkt:
0.75(185)-18.5=138.75-18.5=120.25
0.65(185)=120.25
Answer:

Step-by-step explanation:
From similar triangles, see diagram in attachment

We solve for
to obtain,

The formula for calculating the volume of a cone is

We substitute the value of
to obtain,

This implies that,

We now differentiate both sides with respect to
to get,

We were given that water is drained out of the tank at a rate of 
This implies that
.
Since we want to determine the rate at which the depth of the water is changing at the instance when the water in the tank is 8cm deep, it means
.
We substitute this values to obtain,



