Answer:
Step-by-step explanation:
p = power washer and g = generator
6p + 6g = 90 .....multiply by 4
4p + 8g = 100 ....multiply by -6
---------------------
24p + 24g = 360 (result of multiplying by 4)
-24p - 48g = -600 (result of multiplying by -6)
---------------------add
-24g = - 240
g = -240 / -24
g = 10 <=== the generator cost $ 10 per hr
6p + 6g = 90
6p + 6(10) = 90
6p + 60 = 90
6p = 90 - 60
6p = 30
p = 30/6
p = 5 <==== the power washer costs $ 5 per hr
check...
4p + 8g = 100
4(5) + 8(10) = 100
20 + 80 = 100
100 = 100 (correct)
Answer:

Step-by-step explanation:
The surface area of a square pyramid is the sum of the area of the squared base + 4 times the area of each triangular face, therefore:

where:
is the area of the base, where
L is the length of the base
is the area of each triangular face, where
h is the height of the face
Substituting,

For the model in this problem,
L = 12
h = 8
Therefore, the surface area here is:

Answer:
n =-19
Step-by-step explanation:
3* (n+7) = -36
Distribute
3n+21 = -36
Subtract 21 from each side
3n+21-21 = -36-21
3n = -57
Divide by 3
3n/3 = -57/3
n =-19
Answer:
4 inches
Step-by-step explanation:
The line that is perpendicular to the bottom of the trapezoid is the height.