SOLUTION: I am trying to solve for x (to find the x intercept) in the equation y=(-1/2)x^2+2x+10. I got the y intercept (10) by "letting x=0", but when I try to do the same, "letting y=0",

Algebra.Com
Question 264395: I am trying to solve for x (to find the x intercept) in the equation
y=(-1/2)x^2+2x+10. I got the y intercept (10) by "letting x=0", but when I try to do the same, "letting y=0", I get confused due to the fraction and exponent and do not know how to isolate the x. Can someone please explain this to me. Thank you!
Found 2 solutions by richwmiller, Alan3354:
Answer by richwmiller(17219)   (Show Source): You can put this solution on YOUR website!

You need to use the quadratic formula to solve for x
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation (in our case ) has the following solutons:



For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=24 is greater than zero. That means that there are two solutions: .




Quadratic expression can be factored:

Again, the answer is: -2.89897948556636, 6.89897948556636. Here's your graph:
Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
y=(-1/2)x^2+2x+10
(-1/2)x^2+2x+10 = 0
Multiply by -2
x^2 - 4x - 20 = 0
Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation (in our case ) has the following solutons:



For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=96 is greater than zero. That means that there are two solutions: .




Quadratic expression can be factored:

Again, the answer is: 6.89897948556636, -2.89897948556636. Here's your graph:

-----------
x = 2 +/- 2sqrt(3)

RELATED QUESTIONS

2x+y=4 I am trying to find the x and y intercept of the equation (answered by whty89)
I am trying to change this into slope-intercept form. The equation is 2x + 5y = 12. I... (answered by Alan3354,richwmiller)
I have the following problem. I will be honest, it is for homework, so the answer is not... (answered by stanbon,ankor@dixie-net.com,Fombitz)
Emergency!!!!! Buried and need help in understanding these problems. (1) Find the... (answered by fractalier)
For the function f(x)=x squared + 2/x-1 How do I check for symmetry and find the... (answered by jim_thompson5910)
HI!! I am trying to figure out : Use the equation 3x + 5y = 0 1. To Rewrite the... (answered by Fombitz)
Given (10, –2) with a slope of –1, I find an equation for the line by plugging in values... (answered by MathLover1)
find the x and y intercept for the given equation: y = 12 x -10 i used a 0 in the... (answered by themasterofcircuits)
I am trying to solve the equation: (1/(x-3))+(1/(x+3))=(10/(x^2-9)) Thanks in... (answered by ankor@dixie-net.com)