1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Alexxandr [17]
4 years ago
15

Write the equation for the parabola that has x− intercepts (1.2,0) and (4,0) and y− intercept (0,12).

Mathematics
2 answers:
disa [49]4 years ago
6 0
<span>y = 2.5x^2 - 13x + 12
   The equation for a parabola is a quadratic equation of the form
 y = ax^2 + bx + c
   So let's calculate a, b, and c.
First thing to note is that we have the y-intercept, so x is 0. That means that we have
 12 = a*0^2 + b*0 + c
 12 = 0 + 0 + c
 12 = c

   So we now know c which is 12.

   Now with the two intercepts we have
 ax^2 + bx + 12 = 0 where x is 1.2 or 4. So let's set them equal to each other. Then solve for b in terms of a.

   a(1.2)^2 + b(1.2) + 12 = a(4)^2 + b(4) + 12
a(1.44) + b(1.2) = a(16) + b(4)
 1.44a + 1.2b = 16a + 4b
 1.44a = 16a + 2.8b
 -14.56a = 2.8b
 -5.2a = b

   Let's substitute -5.2a for b in the equation we have so far and solve for a.
 y = ax^2 + bx + 12
  y = ax^2 - 5.2ax + 12

    Substitute known x & y value
 0 = a*4^2 - 5.2a*4 + 12
 0 = 16a - 20.8a + 12
 0 = -4.8a + 12
 -12 = -4.8a
 2.5 = a

   We now have both a = 2.5 and c = 12. Let's get b.
 -5.2a = b
 -5.2*2.5 = b
 -13 = b

   So the final equation is: y = 2.5x^2 - 13x + 12

   Let's verify with the given points.
 x = 1.2
 y = 2.5x^2 - 13x + 12
 y = 2.5*1.2^2 - 13*1.2 + 12
 y = 3.6 - 15.6 + 12
 y = 0

   x = 4
 y = 2.5x^2 - 13x + 12
 y = 2.5*4^2 - 13*4 + 12
 y = 2.5*16 - 13*4 + 12
 y = 40 - 52 + 12
 y = 0 x = 0
 y = 2.5x^2 - 13x + 12
 y = 2.5*0^2 - 13*0 + 12
 y = 2.5*0 - 13*0 + 12
 y = 0 - 0 + 12 = 12

   And all three given points confirmed.</span>
zzz [600]4 years ago
3 0
Equation of a parabola is written in the form of f(x)=ax²+bx+c.
The equation passes through points (4,0), (1.2,0) and (0,12), therefore; 
 replacing the points in the equation y = ax² +bx+c 
we get  0 = a(4)²+b(4) +c   for (4,0)
             0 = a (1.2)²+ b(1.2) +c for (1.2,0)
             12 = a(0)² +b(0) +c   for (0,12)
simplifying the equations we get
16a + 4b + c = 0
1.44a +1.2b + c = 0
+c = 12
thus the first two equations will be
16a + 4b = -12
1.44 a + 1.2b = -12 solving simultaneously 
the value of a = 5/2 and b =-13
Thus, the equation of the parabola will be given by;
 y= 5/2x² - 13x + 12 or y = 2.5x² - 13x + 12


You might be interested in
On a unit circle, the vertical distance from the x-axis to a point on the perimeter of the circle is twice the horizontal
tia_tia [17]

Answer:

  (2/5)√5 ≈ 0.894427

Step-by-step explanation:

You require the y-coordinate of the point that satisfies two equations:

  x^2 +y^2 = 1

  y = 2x

Substituting for x, we have ...

  (y/2)^2 +y^2 = 1

  y^2(5/4) = 1

  y^2 = 4/5

  y = (2/5)√5 ≈ 0.894427

The sine of the angle is (2/5)√5 ≈ 0.894427.

8 0
4 years ago
What is the square root of 11 times 8
Amanda [17]

i think the answer is 88 i hope i helped

7 0
3 years ago
Read 2 more answers
What is the best estimate for the length of a book?
Andreyy89

Answer is 20 centimeters

Step-by-step explanation:

7 0
3 years ago
I) -7s (S-4t-3u) <br><br><br>ii) -4c (2c-5d)<br>​
umka21 [38]
I) -7s^2+28st+21su
II) -8c^2+20cd
3 0
3 years ago
Read 2 more answers
Original cost of a book: $13.95; markdown by 2/3
lora16 [44]

The price would be $9.30

8 0
4 years ago
Read 2 more answers
Other questions:
  • I know it's late but im having trouble in math.I need an exper to help for BRAINLEST and extra points​
    5·1 answer
  • What are the cordinates
    7·1 answer
  • Express (7x + 3)(x + 3 ) as a polynomial
    5·1 answer
  • Yo guys can i get some help plz
    15·1 answer
  • Help is appreciated
    5·1 answer
  • I need help immediately 156 1/42- 55 1/6
    11·1 answer
  • Pls help with me and my chrome homework
    13·1 answer
  • HELP!!!<br> A triangle and its angle measures are shown in the diagram. What is the value of x?
    8·1 answer
  • The product of the roots of a quadratic equation 2x²-5x+3=0 is 5/2 if it is correct give reason
    15·1 answer
  • Diagram 1 shows absolute function of f(x)= 3x-1a)State the domain for that functionb)State the value of a
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!