SOLUTION: Find the x-intercepts. y = x^2 – 7x – 2 What is the process to solve this problem? Any assistance is appreciated.

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Find the x-intercepts. y = x^2 – 7x – 2 What is the process to solve this problem? Any assistance is appreciated.       Log On


   

Question 89760: Find the x-intercepts.
y = x^2 – 7x – 2
What is the process to solve this problem? Any assistance is appreciated.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
y = x^2 – 7x – 2
:
The x intercepts occur when y = 0, therefore:
x^2 - 7x - 2 = 0
:
To the value of x, in this equation we have to us the quadratic formula:
:
In this equation a=1; b=-7; c=-2
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
:
x+=+%28-%28-7%29+%2B-+sqrt%28+-7%5E2+-+4+%2A+1+%2A+-2+%29%29%2F%282%2A1%29+
:
x+=+%28%2B7+%2B-+sqrt%28+49+-+%28-8%29+%29%29%2F%282%29+; a minus a minus is a plus
:
x+=+%28%2B7+%2B-+sqrt%28+49+%2B+8+%29%29%2F%282%29+;
:
x+=+%28%2B7+%2B-+sqrt%28+57+%29%29%2F%282%29+;
:
Solution 1:
x+=+%28%2B7+%2B7.55%29%2F%282%29+;
x+=+14.55%2F2;
x = +7.275
:
Solution 2:
x+=+%28%2B7+-+7.55%29%2F%282%29+;
x+=+-.55%2F%282%29+;
x = -.275
:
:
Check both solutions in the original equation