Answer:
600 ft³
Step-by-step explanation:
Base area: B
Base is triangle
base = 12 ft and height = 5 ft
Area of triangle = B = 

H = 20 ft
Volume = B * H
= 30 * 20
= 600 ft³
-3x+7y=5 (x2) -> -6x+14y=10
-6x+14y=10
-8x+14y=-10
——————— -
2x=20
x=20/20
x=1
Susbstitute x=1,
-8x+14y=-10
-8(1)+14y=-10
-8+14y=-10
14y=-10+8
14y=-2
y=-2/14
y=-1/7
I hope it helps
The expanded answer is 2025m^2+1620m+324
I hope this helps you out! Take care