Posted by **priya** on Monday, November 1, 2010 at 10:24pm.

I don't get how to do this. I'm so lost please help me.

Determine the equation of the parabola with roots 2+√3 and 2-√3, and is passing through the point (2,5)

this is what i did but its the wrong answer:

y= a[x + (2+√3)] [x+(2-√3)]

5= a[2 + (2+√3)] [2+(2-√3)]

5= a[ 4+√3] [4-√3]

5= 12.99a

a= 0.38

therefore,y = 0.38[x+(2+√3)][x+(2-√3)]

but this is wrong

- grade 11 math -
**Reiny**, Monday, November 1, 2010 at 10:51pm
If you know a root and form the factors you have to subtract the root.

e.g. if x = 3, then the corresponding factor is (x-3)

so you should have had

y = a[x - (2+√3)][x-(2-√3)]

= a(x-2-√3)(x-2+√3)

= a(x^2 - 4x +1)

now sub in the point (2,5)

5 = a(4 - 8 + 1)

a = -5/3

y = (-5/3)[x^2 - 4x + 1)

## Answer this Question

## Related Questions

- Math - Find an equation of the line that bisects the obtuse angles formed by the...
- Algebra 2 - Use the distance formula to find the equation of a parabola. Focus...
- 8th grade algebra: radicals - please help me solve these 1. 2√5/8 + 4&#...
- math grade 11 - i need help with this quretsion ; i dont know if im right, and i...
- math grade 11 - i need help with this quretsion ; i dont know if im right, and i...
- algebra 1 help - simplifying square roots 1) find volume of this prism? v=bwh b...
- Math - Determine the exact value of cos 465 degrees a) √3 + √2/2 b...
- math - How would I come about to the solution and what the answers to the ...
- Algebra - How would i complete these problems? 1. (√6mn)^5 2. ^3√16x...
- maths - I will be thankfull to you if you help me to solve the below problem: 6...