Answer:
A) 10x + 8 = 21
B) x = 1.3
Step-by-step explanation:
2(2x + 3) + 2(x + 1) + 4x = 21
4x + 6 + 2x + 2 + 4x = 21
10x + 8 = 21
10x = 13
x = 1.3 cm
 
        
             
        
        
        
Answer:
y = x + 15
Step-by-step explanation:
If two lines are perpendicular to each other, they have opposite slopes.
The first line is y = - x - 2. Its slope is -1. A line perpendicular to this will have a slope of 1.
Plug this value (1) into your standard point-slope equation of y = mx + b.
y = 1x + b or y = x + b
To find b, we want to plug in a value that we know is on this line: in this case, it is (-5, 10). Plug in the x and y values into the x and y of the standard equation.
10 = (-5) + b
Simplify.
10 = -5 + b
Now, add 5 to both sides to isolate b.
15 = b
Plug this into your standard equation.
y = x + 15
This equation is perpendicular to your given equation (y = -x - 2) and contains point (-5, 10)
Hope this helps!
 
        
             
        
        
        
Answer:

Step-by-step explanation:
The formula ogf a volume of  a pyramid:

B - area of a base
H - height
We have a base length a = 5 in and a height H = 9 in.
In the base we have a square. The formula of an area of a square is:

Substitute:

Calculate the volume:

 
        
             
        
        
        
Answer:
2(4+x)
Step-by-step explanation:
"Twice the sum of" tells us it will be the equation times two
"the sum of four and a number" is easy, thats 4 + x
The second number is x because the number is not specified so we need a place holder, x in this case, to tell us that the number is not given.
All this put together = twice the sum of four and a number, or <u>2(4+x)</u>