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Question 3(Multiple Choice Worth 2 points)
(06.04 MC)
Two water balloons were launched into the air at different moments and collided. The water balloons were modeled by the quadratic functions: y=-7x²+26x+3 and y=-6x² +23x+
5, where y represents the height in meters and x represents the time in seconds after the launch. What is the time, in seconds, that the balloons collided at the highest point?
2.0 seconds
2.25 seconds
2.5 seconds
2.75 seconds

Respuesta :

Answer:

2.0 seconds

Step-by-step explanation:

Given quadratic functions:

[tex]\begin{cases}y=-7x^2+26x+3\\y=-6x^2 +23x+5\end{cases}[/tex]

To find the time, in seconds, that the balloons collided at the highest point, substitute one equation into the other equation and rearrange to equal zero:

[tex]\begin{aligned}-6x^2+23x+5 & = -7x^2+26x+3\\-6x^2+23x+5+7x^2 & = -7x^2+26x+3+7x^2\\x^2+23x+5 & = 26x+3\\x^2+23x+5-26x & = 26x+3-26x\\x^2-3x+5& = 3\\x^2-3x+5-3& = 3-3\\x^2-3x+2& = 0\end{aligned}[/tex]

Factor the quadratic:

[tex]\begin{aligned}x^2-3x+2 & = 0\\x^2-2x-x+2 & = 0\\x(x-2)-1(x-2) & = 0\\(x-1)(x-2) & = 0\\\end{aligned}[/tex]

Apply the zero-product property to solve for x:

[tex]\implies (x-1)=0 \implies x=1[/tex]

[tex]\implies (x-2)=0 \implies x=2[/tex]

Therefore, the balloons collided at 1 second and 2 seconds.  

To find at which time the highest point of collision occured, substitute both values of x into one of the functions:

[tex]f(1)=-6(1)^2 +23(1)+5=22[/tex]

[tex]f(2)=-6(2)^2 +23(2)+5=27[/tex]

Therefore, the time, in seconds, that the balloons collided at the highest point is 2.0 seconds.

Learn more about quadratic systems of equations here:

https://brainly.com/question/27930827

Equate both and solve

  • -7x²+26x+3=-6x²+23x+5
  • -7x²+6x²+26x-23x+3-5=0
  • -x²+3x-2=0
  • x²-3x+2=0
  • (x-2)(x-1)=0

x=2,1

The collisions happen at 1s and 2s

As only 2s is included in our options option A is correct