SOLUTION: solve using Q. F. Formula x=-b+- sq b-4ac/2a 2x^2+x-1=0 the answer is 1/2,1 I'm new to these so please help....thanks!

Algebra ->  Expressions-with-variables -> SOLUTION: solve using Q. F. Formula x=-b+- sq b-4ac/2a 2x^2+x-1=0 the answer is 1/2,1 I'm new to these so please help....thanks!      Log On


   

Question 84683: solve using Q. F. Formula x=-b+- sq b-4ac/2a

2x^2+x-1=0 the answer is 1/2,1

I'm new to these so please help....thanks!
Answer by uma(370) About Me  (Show Source):
You can put this solution on YOUR website!
If the equation is of the form ax^2 + bx + c = 0, then by formula,
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
The given equation is 2x^2 + x - 1 = 0,
where a = 2, b = 1 and c = -1.
So plugging in the above formula,
x+=+%28-1+%2B-+sqrt%28+1%5E2-4%2A2%2A%28-1%29+%29%29%2F%282%2A2%29+
==> x+=+%28-1+%2B-+sqrt%28+1%2B8+%29%29%2F%284%29+
==> x+=+%28-1+%2B-+sqrt%28+9+%29%29%2F%284%29+
==> x+=+%28-1+%2B-+3%29%2F%284%29+
==> x = (-1+3)/4 and x = (-1-3)/4
==> x = 2/4 and x = -4/4
==> x = 1/2 and x = -1

Good Luck!!!