<span>The answer is this 20t2 + 9t – 20. Go look up a video for foiling </span>
K = Kevin's age
D = Daniel's age
K = 3D
K - 4 = 5(D - 4)
Plug in 3D for the K values in the second equation.
3D - 4 = 5(D - 4) Use the Distributive Property
3D - 4 = 5D - 20 Add 4 to both sides
3D = 5D - 16 Subtract 5D from both sides
-2D = -16 Divide both sides by -2
D = 8
Now, plug that D value into the original equation.
K = 3D Plug in the D value
K = 3(8) Multiply
K = 24
Finally, you can double check your math.
4 years ago, Daniel would've been 4 and Kevin would be 20, so Kevin would've been 5 times as old as Daniel. And 8 x 3 = 24.
So, Kevin is 24.
Always eliminate the first one before moving on. Remember to drop down monomials, like you would a normal division problem.
2x² + 10x + 18
__________________
x + 3 | 2x³ + 16x² - 12x + 9
-(2x³ + 6x²)
-------------------------------
10x² - 12x
-(10x² - 30x)
-----------------------------
+ 18x + 9
- (18x + 54)
----------------------
-45
2x² + 10x + 18 R: -45/x + 3 is your answer R: = remainder
hope this helps
9514 1404 393
Answer:
- 320 m after 8 seconds
- 5.6 seconds, 10.4 seconds to height of 290 m
Step-by-step explanation:
To find the height at 8 seconds, evaluate the formula for t=8.
S(t) = -5t^2 +80t
S(8) = -5(8^2) +80(8) = -320 +640 = 320
The height of the rocket is 320 meters 8 seconds after takeoff.
__
To find the time to 290 meters height, solve ...
S(t) = 290
290 = -5t^2 +80t
-58 = t^2 -16t . . . . . . . divide by -5
6 = t^2 -16t +64 . . . . . complete the square by adding 64
±√6 = t -8 . . . . . . . . . take the square root
t = 8 ±√6 ≈ {5.551, 10.449}
The rocket is at 290 meters height after 5.6 seconds and again after 10.4 seconds.
