13x = 39 can replace 3x + 5y = 59 in the original system and still produce the same solution.
Answer:
x = 1 or x = −6
Step-by-step explanation:
Step 1: Subtract 18 from both sides.
3x2+15x−18=18−18
3x2+15x−18=0
Step 2: Factor left side of equation.
3(x−1)(x+6)=0
Step 3: Set factors equal to 0.
x−1=0 or x+6=0
x=1 or x=−6
You do the sum(40) subtracted by 8, the answer from that divided by 2 since Erin's two times younger.
40-8=32
32÷2=16
Then if you want to check it you do the opposite and get the same sum(40) so 16×2=32 and 32+8=40
The volume of a cylinder with a radius r and a height h:

The volume of a cone with a radius r and a height h:

Therefore

We have 
Substitute:

Answer: The volume of a cone is equal 10.75 in³