# Math

posted by .

x^2-10x-15=0

I got 5+-2sqrt10/2.

^ Sorry hard to write it out. But basically there is a 5 there, the negative sign is supposed to be under the positive sign, then there is a two outside of the radicand, and inside the radicand is 10, all under 2.

• Math -

The answer is correct if it was meant to be, after cancelling the two's:
5±√(10)

• Math - correction -

The answer is correct if it was meant to be (without the 2 in the denominator):
5±2√(10)

• Math -

Where does that two in the denominator go? Since it has to cancel out with all terms.

• Math -

x=(-b±sqrt(b²-4ac))/2a
a=1
b=-10
c=-15
so substituting,
x=(10±sqrt((-10)²-4(1)(-15)))/2
=(10±sqrt(160))/2
=(10±4sqrt(10))/2
=5±2sqrt(10)

You may have (like I did) subtracted 4ac (and got 40) instead of adding to get 160.

## Similar Questions

1. ### Math ,help

how can i simplify this more its for the following problem: Problem #22 solve by using the quadratic formual. 5x^2-4x+1=0 this is where i am but i do not know how to go further. x = (4 (+/-) sqrt (-4))/(10) Problem #23 Solve by completing …
2. ### Math

Use the quadratic formula to solve each of the following quadratic equations... 1. 2x^2-5x=3 2. 3x^2-2x+1=0 Rearrange the equation in quadratic formula form. 2x^2 -5x -3 = 0 Then use the formula. Tell me what you don't understand about …
3. ### help with solving

x^2+(x-2)^2 = (2x-6)^2 solve for x. thanks so much. Please keep in mind that tutors here won't simply do your work for you . I'm sure you'll get a better response if you show your work as far as you can get , so tutors will know where …
4. ### Math

How do you graph the quadratic formula x^2-10x=11?
5. ### algebra II

I'm quite clueless as to how to solve this. I know the quadratic equation but am not sure how to get this equation into the format to plug in to the quadratic... Solve the quadratic equation using the formula [1/(1+x)]-[1/(3-x)]=(6/35) …
6. ### math

15t^2+7t=2 The quadratic formula tells you that the solutions are: t = [-b +/-sqrt (b^2 - 4ac]/ (2a) In this case, a = 15, b = 7 and c = -2 solve the equation for t. What values for t will you get when you substitute the values you …