Your surface area is: S=x^2+4xh=84 square inches and h=2 inches; so you get:
x^2+(4×2)x=84
x^2+8x-84=0 qhich is a quadratic equation. Using the quadratic formula you get two results for x:
x1=-14 and x2=6
choose the second (positive)
Answer: A) 10
4+8+21+9+12+6=60
60/6= 10
To find the mean, you’ll add all the numbers and then divided be however many there are.
Step-by-step explanation:
<em>LOOK AT THE PICTURE</em>
In ΔABC:

In ΔADC

In ΔBCD

Answer:
x=-12
Step-by-step explanation:

To remove the denominator we take LCD
LCD of 3 and 4 is 12
In the second step we multiply the whole equation by 12 not only the fractions

Now the denominator gets removed
1/3 * 12 = 4 , also 3/4 times 12 = 3*3 = 9
4x - 48 = 9x + 12
Subtract 9x on both sides
-5x - 48 = 12
Now add 48 on both sides
-5 x = 60
Divide both sides by -5
so x= -12
The value of x= -12
We know that HJ + JK = HK
So lets substitute each part for their equation.
(2x + 5) + (3x - 7) = 18
Combine like terms
5x -2 = 18
Add 2 to both sides to eliminate it
5x = 20
Divide both sides by 5
x = 4
Let me know if you have any questions about this! :)