21 because it is being multiplied

For proportions and to find x we have to cross multiply
8 × (x) = 3 × 2.4
8x = 7.2
Divide by 8 to isolate x

8 and 8 cancels out
x = 0.9
Just subsitute 8 for n
1/2(8)^2-1/2(8)
1/2(64)-4
32-4
28
D
Answer:
A. y ≥ 2x – 2
Step-by-step explanation:
(See the imagine for reference)
Let’s solve where they have a triangle, so the height is 9 cm, the base is 3 cm:
1/2 • 9 • 3 = 13.5
Since there’s 2 triangles we do:
13.5(2) = 27
Now the rectangle in the middle, where the height is 9cm and the base is 12cm:
12 • 9 = 108
Add up the areas:
108 + 27 = 135