It takes 4.3 seconds for the rocket to return to earth.
The equation is:

where -9.8m/sec² is the acceleration due to gravity, v₀ is the initial velocity, and h₀ is the initial height. We will go from the assumption that the rocket is launched from the ground, so h₀=0, and we are told that the initial velocity, v₀, is 42. This gives us:

We will use the quadratic formula to solve this. The quadratic formula is:

Plugging in our information we have:

x=0 is when the rocket is launched; x=4.3 is when the rocket lands.
<span>x + 1/2 = 3/4
</span><span>x + 2/4 = 3/4
x = 3/4 - 2/4
x = 1/4
answer
</span><span>x = 1/4</span>
Multiply the top and bottom by 2
6/14 = 12/28
now solving for the 2nd part is more difficult i would use cross multiply and divide . Multiply 6 and 12 which equals 72 then divide by 14 which will get you 5.142857 or 5 36/7= 71/14
Answer:
20
Step-by-step explanation:
Since both triangles are similar, then the ratio is 18:6, which is 3:1
Triangle ABC is 3 times the size of DEC.
So, 1/3 of 30 is 10, and 30-10 is 20.