That's a right angled triangle.
Hope this helps!
Answer:
-63
Step-by-step explanation:
9 - (2×3) × 12
9 - (6 × 12)
9 - 72
= -63
Answer:
The area of the rectangle is increasing at a rate of 84 square centimeters per second.
Step-by-step explanation:
The area for a rectangle is given by the formula:

Where <em>w</em> is the width and <em>l</em> is the length.
We are given that the length of the rectangle is increasing at a rate of 6 cm/s and that the width is increasing at a rate of 5 cm/s. In other words, dl/dt = 6 and dw/dt = 5.
First, differentiate the equation with respect to <em>t</em>, where <em>w</em> and <em>l</em> are both functions of <em>t: </em>
![\displaystyle \frac{dA}{dt}=\frac{d}{dt}\left[w\ell]](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Cfrac%7BdA%7D%7Bdt%7D%3D%5Cfrac%7Bd%7D%7Bdt%7D%5Cleft%5Bw%5Cell%5D)
By the Product Rule:

Since we know that dl/dt = 6 and that dw/dt = 5:

We want to find the rate at which the area is increasing when the length is 12 cm and the width is 4 cm. Substitute:

The area of the rectangle is increasing at a rate of 84 square centimeters per second.
Answer:
length = 18 ft
Step-by-step explanation:
Let w = width
L = w+7
Area = l*w
198 = (w+7) (w)
Distribute
198 = w^2 +7w
Subtract 198 from each side
0 = w^2 +7w -198
Factor
What 2 numbers multiply to -198 and add to 7
18* -11 = -198
18+-11 = 7
0=(w+18) (w-11)
Using the zero product property
w+18 =0 w-11=0
w= -18 w=11
We cannot have negative width so w=11
We want the length
l = w+7
l = 11+7 = 18